Street lights illuminate the Gaza skyline as the sun rises over fishermen as they bring their catch into the port in Gaza City, February 14, 2019. Gaza's fisherman are often only able to fish a few miles from the coast - the distance varies. Israeli gunboats stop them going farther. REUTERS/Dylan Martinez SEARCH "MARTINEZ GAZA" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Secretary of State John Kerry, left, talks with Vo Van Tam, 70, second from right, who was a former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool TPX IMAGES OF THE DAY

Secretary of State John Kerry, left, talks with Vo Van Tam, 70, second from right, who was a former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, smiles as he talks with Vo Van Tam, 70, second from right, who was a former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

A man waves as the boat with Secretary of State John Kerry aboard travels past him, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry rides a boat, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry rides a boat, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool TPX IMAGES OF THE DAY

Senior Advisor to the Secretary David Thorne, rides a boat with Secretary of State John Kerry, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry rides a boat, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

U.S. Secretary of State John Kerry, top, rides a boat with Senior Advisor to the Secretary David Thorne, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, with Dartmouth College associate professor of history Edward Miller, use a map as they ride a boat on the river and identify the spot where the battle took place from which Kerry later received the Silver Star, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, center, rides a boat with Senior Advisor to the Secretary David Thorne, and Dartmouth College associate professor of history Edward Miller, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, right, and others ride a boat Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Vo Van Tam, 70, right, who was a member of the former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, stands after talking with Secretary of State John Kerry after his tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, with Dartmouth College associate professor of history Edward Miller, use a map as they ride a boat on the river and identify the spot where the battle took place from which Kerry later received the Silver Star, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, talks with Vo Van Tam, 70, right, who was a member of the former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, talks with Vo Van Tam, 70, right, who was a member of the former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry uses a map to identify the location where the action took place for which he received the Silver Star, while on a boat tour Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, shakes hands with Vo Van Tam, 70, right, who was a member of the former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, greets with Vo Van Tam, 70, right, who was a member of the former Viet Cong guerrilla, who took part in the attack on Kerry's Swift Boat in Feb. 28, 1969, while on a tour of the region Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool

Secretary of State John Kerry, left, with Dartmouth College associate professor of history, use a map as they ride a boat on the river and identify the spot where the battle took place from which Kerry later received the Silver Star, Saturday, Jan. 14, 2017 in the Mekong River Delta, Vietnam. Kerry once patrolled these waters on a U.S. naval gunboat and received the Silver Star for his actions. REUTERS/Alex Brandon/Pool TPX IMAGES OF THE DAY

A Laotian soldier walks up a stairway in front of an army patrol boat on the Mekong river port of Mouang Mom on the Laos side of the Golden Triangle, the border between Laos, Myanmar and Thailand March 2, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A Chinese paramilitary policeman guards a base at the Mekong river port of Mouang Mom on the Laos side of the Golden Triangle, near the border between Laos, Myanmar and Thailand March 2, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A long boat sails near the port of Chiang Saen on the Thai side of the Golden Triangle at the border between Thailand, Laos and Myanmar in the Mekong river March 3, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A Chinese billboard is seen on the Mekong river close to Guan Lei port at the triple border between China, Laos and Myanmar March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A soldier from Laos (L) and a Chinese paramilitary police officer stand at an army post on the Mekong river at the Laos port of Xieng Kok at the border between Laos and Myanmar March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES TPX IMAGES OF THE DAY

Thai soldiers stand guard at Ban Kaen Kai operation base on the Mekong river at the border between Thailand and Laos March 3, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A cargo ship where Chinese sailors were killed in 2011 is seen at the port of Chiang Saen on the Thai side of the Golden Triangle at the triple border between Thailand, Laos and Myanmar on the Mekong river March 2, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A Thai soldier stands guard at Ban Kaen Kai operation base on the Mekong river at the border between Thailand and Laos March 3, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A man sits on a long boat on the Mekong river close to Guan Lei port at the triple border between China, Laos and Myanmar March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

Flags flutter on a boat while a delegates from China's Narcotics Control Bureau, the United Nations Office on Drugs and Crime (UNODC), Laos, Myanmar and Thailand travel on an inspection trip on the Mekong river near the border between China, Laos and Myanmar March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A Thai military post is seen near the port of Chiang Saen on the Thai side of the Golden Triangle at the triple border between Thailand, Laos and Myanmar in the Mekong river March 3, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES TPX IMAGES OF THE DAY

A Thai soldier takes part in training at the port of Chiang Saen on the Thai side of the Golden Triangle at the border between Thailand, Laos and Myanmar on the Mekong river March 3, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A man sits on a long boat on the Mekong river close to Guan Lei port at the triple border between China, Laos and Myanmar March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES TPX IMAGES OF THE DAY

A long boat sails near the port of Chiang Saen on the Thai side of the Golden Triangle at the border between Thailand, Laos and Myanmar on the Mekong river March 2, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A Thai soldier stands at Ban Kaen Kai operations base on the Mekong river at the border between Thailand and Laos March 3, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A man sits on a long boat on the Mekong river near the Golden Triangle at the border between Laos, Myanmar and Thailand March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

A limousine waits for customers at the entrance to The Blue Shield casino operated by the Kings Romans Group in the Golden Triangle special economic zone on the banks of the Mekong river on the Laos side near the triple border between Laos, Myanmar and Thailand March 2, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

The Blue Shield casino operated by the Kings Romans Group stands in the Golden Triangle special economic zone on the banks of the Mekong river in Laos near the border between Laos, Myanmar and Thailand March 2, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

Chinese cargo ships sail on the Mekong river near the Golden Triangle at the border between Laos, Myanmar and Thailand March 1, 2016. Patrols on the Mekong River by the Laotian army and Myanmar police have subdued pirates who once robbed cargo ships with impunity. But drug production and trafficking in the region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and Chinese armed police. The United Nations Office on Drugs and Crime estimates that Southeast Asia's trade in heroin and methamphetamine was worth $31 billion in 2013. REUTERS/Jorge Silva SEARCH "SILVA MEKONG" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

Gunboats patrol Manila Bay outside the Sofitel, where U.S. President Barack Obama is residing, during the Asia-Pacific Economic Cooperation (APEC) Summit in Manila, Philippines, November 19, 2015. REUTERS/Jonathan Ernst

Gunboats patrol Manila Bay outside the Sofitel, where U.S. President Barack Obama is staying during the APEC Summit in Manila, Philippines, November 19, 2015. REUTERS/Jonathan Ernst

Gunboats patrol Manila Bay outside the Sofitel, where U.S. President Barack Obama is staying during the APEC Summit in Manila, Philippines, November 19, 2015. REUTERS/Jonathan Ernst

People hold Palestinian flags next to sheets stained in red paint, mimicking blood, depicting the children, who medics said was killed by a shell fired by an Israeli naval gunboat, on a beach in Gaza City on July 16, during a protest against Israel's military action in Gaza, at La Constitucion square in Malaga, southern Spain July 22, 2014. Israel pounded targets across the Gaza Strip on Tuesday, saying no ceasefire was near as top U.S. and United Nations diplomats pursued talks on halting the fighting that has claimed more than 600 lives. REUTERS/Jon Nazca (SPAIN - Tags: CIVIL UNREST POLITICS CONFLICT) SOCIETY)

People hold a banner next to sheets stained in red paint, mimicking blood, depicting the children, who medics said were killed by a shell fired by an Israeli naval gunboat, on a beach in Gaza City on July 16, during a protest against Israel's military action in Gaza, at La Constitucion square in Malaga, southern Spain July 22, 2014. Israel pounded targets across the Gaza Strip on Tuesday, saying no ceasefire was near as top U.S. and United Nations diplomats pursued talks on halting the fighting that has claimed more than 600 lives. The banner reads, "Israel kills. The international community is silent". REUTERS/Jon Nazca (SPAIN - Tags: CIVIL UNREST POLITICS CONFLICT)

People stand next to sheets stained in red paint, mimicking blood, depicting the children who medics said was killed by a shell fired by an Israeli naval gunboat, on a beach in Gaza City on July 16, during a protest against Israel's military action in Gaza, at La Constitucion square in Malaga, southern Spain July 22, 2014. Israel pounded targets across the Gaza Strip on Tuesday, saying no ceasefire was near as top U.S. and United Nations diplomats pursued talks on halting the fighting that has claimed more than 600 lives. REUTERS/Jon Nazca (SPAIN - Tags: CIVIL UNREST POLITICS CONFLICT)

Israeli soldiers stand around their armoured personnel carriers (APCs) across from the northern Gaza Strip, as flares from Israel light the sky, July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli soldiers stand on top of their tanks and armoured personnel carriers (APCs) across from the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Smoke billows near a building complex in the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli soldiers gather for a chat with their commander across from the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS MILITARY CONFLICT TPX IMAGES OF THE DAY)

Israeli soldiers stand on top of their tanks across from the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli soldiers put on their gear on the side of a road across from the Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY TPX IMAGES OF THE DAY CONFLICT)

Israeli soldiers stand on top of their tanks and armoured personnel carriers (APCs) across from the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY TPX IMAGES OF THE DAY CONFLICT)

Israeli military vehicles manoeuvre outside the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Ronen Zvulun (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli tanks manoeuvre outside the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Ronen Zvulun (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli military armoured personnel carriers (APCs) drive in a convoy across from the Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Ronen Zvulun (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli soldiers gear up on the side of a road opposite Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/Baz Ratner (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY)

Israeli soldiers gesture as they ride their armoured personnel carrier across from the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Ronen Zvulun (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

An Israeli soldier sits on top of his tank across the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Ronen Zvulun (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT)

Israeli soldiers stand around their tanks and armoured personnel carriers (APCs) opposite the northern Gaza Strip July 18, 2014. Israel intensified its land offensive in Gaza with artillery, tanks and gunboats on Friday and warned it could "significantly widen" an operation Palestinian officials said was killing ever greater numbers of civilians. The Israeli land advance followed 10 days of barrages against Gaza from air and sea, hundreds of rockets fired by Hamas into Israel and failed attempts by Egypt, a broker of ceasefires in previous Israeli-Palestinian flare-ups, to secure a truce. REUTERS/ Ronen Zvulun (ISRAEL - Tags: POLITICS CIVIL UNREST MILITARY CONFLICT TPX IMAGES OF THE DAY)