Fighters from Libyan forces allied with the U.N.-backed government take position as smoke rises during a battle with Islamic State militants in Sirte, Libya September 22, 2016. REUTERS/Ismail Zitouny 

A fighter from Libyan forces allied with the U.N.-backed government moves through the neighborhood number three in Sirte to go into a front line fighting position with Islamic State militants, Libya September 22, 2016. REUTERS/Ismail Zitouny

A female Kurdish fighter from the People's Protection Units (YPG) carries a walkie-talkie as she stands in the Ghwairan neighborhood of Hasaka, Syria, August 22, 2016. REUTERS/Rodi Said 

A woman runs holding a walkie-talkie towards a damaged site after an airstrike on the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria May 31, 2016. REUTERS/Khalil Ashawi 

A Syria Democratic Forces leader (R) uses a walkie talkie and a tablet to communicate with the U.S. alliance operation room on the outskirts of al-Shadadi town, Hasaka countryside, Syria February 19, 2016. REUTERS/Rodi Said TPX IMAGES OF THE DAY

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A fireman calls for reinforcements to extinguish a burning car set ablaze by masked protesters during clashes following protests in a 24-hour general strike by worker's unions against planned pension reforms in central Athens, Greece, February 4, 2016. REUTERS/Yannis Behrakis 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A fireman tries to extinguish a burning car set ablaze by masked protesters during clashes following protests in a 24-hour general strike by worker's unions against planned pension reforms in central Athens, Greece, February 4, 2016. REUTERS/Yannis Behrakis 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A fireman calls for reinforcements to extinguish a burning car set ablaze by masked protesters during clashes following protests in a 24-hour general strike by worker's unions against planned pension reforms in central Athens, Greece, February 4, 2016. REUTERS/Yannis Behrakis 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A fireman calls for reinforcements to extinguish a burning car set ablaze by masked protesters during clashes following protests in a 24-hour general strike by worker's unions against planned pension reforms in central Athens, Greece, February 4, 2016. REUTERS/Yannis Behrakis 

An occupier uses a radio near a gas storage facility at the Malheur National Wildlife Refuge near Burns, Oregon, January 5, 2016. Saturday's takeover of the Malheur National Wildlife Refuge outside the town of Burns, Oregon, marked the latest protest over federal management of public land in the West, long seen by conservatives in the region as an intrusion on individual rights. REUTERS/Jim Urquhart 

FBI and police investigators examine evidence at the scene of the investigation around the area of the SUV vehicle where two suspects were shot by police following a mass shooting in San Bernardino, California December 3, 2015. Authorities on Thursday were working to determine why Syed Rizwan Farook 28, and Tashfeen Malik, 27, opened fire at a holiday party of his co-workers in Southern California, killing 14 people and wounding 17 in an attack that appeared to have been planned. REUTERS/Mike Blake 

An Egyptian police officer uses a walkie-talkie as Mexican embassy members stand outside Dar Al Fouad Hospital, where injured tourists who were mistakenly targeted in a military operation "chasing terrorist elements" are recovering, as Claudia Ruiz Massieu, Mexico's Minister of Foreign Affairs, came to visit them in Cairo, Egypt, September 16, 2015. Mexico's foreign minister said she would meet Egyptian President Abdel Fattah al-Sisi in Cairo on Wednesday and demand thorough investigation of a mistaken army attack that killed eight Mexicans in Egypt's western desert. Mexican Foreign Minister Claudia Ruiz Massieu travelled on Tuesday to Cairo to bring the survivors and remains of the victims back to Mexico. REUTERS/Asmaa Waguih 

People watch as a motorcade with U.S. Secretary of State John Kerry passes, in Cairo August 1, 2015. REUTERS/Brendan Smialowski/Pool 

A traffic officer watches as a motorcade with U.S. Secretary of State John Kerry passes, in Cairo August 1, 2015. REUTERS/Brendan Smialowski/Pool 

A Free Syrian Army fighter talks on a walkie-talkie near a rocket launcher during what they said was preparations for an operation to strike at forces loyal to Syria's president Bashar Al-Assad located in Daraa, July 27, 2015. Picture take July 27, 2015. REUTERS/Alaa Al-Faqir

French and Chadian peacekeepers talk at the Minusma peacekeeping base in Kidal, Mali, July 22, 2015. REUTERS/Adama Diarra 

A keeper carries a 12 week old Sumatran tiger cub in a net during a routine health check in its enclosure at Chester Zoo in Chester northern England March 27 , 2015. The cub, one of 3 born at the zoo, was sexed, vaccinated and micro-chipped. REUTERS/Phil Noble 

A member of the Kurdish traffic police directs traffic in the Kurdish city of Afrin, in Aleppo's countryside March 18, 2015. REUTERS/Mahmoud Hebbo (SYRIA - Tags: POLITICS CIVIL UNREST CONFLICT) 

A woman carries a walkie-talkie as Lebanon's Hezbollah leader Sayyed Hassan Nasrallah appears on a screen to speak at an event to commemorate the deaths of six Hezbollah fighters and an Iranian general killed by an Israeli air strike in Syria on January 18, in Beirut's southern suburbs, January 30, 2015. Nasrallah said on Friday his group did not want war with Israel but was ready for one and had the right to respond to Israeli "aggression" in any time and place. REUTERS/Khalil Hassan (LEBANON - Tags: POLITICS CIVIL UNREST CONFLICT) 

Umm Mohamad, a masters graduate and commander of the all-female Mother Aisha battalion, speaks on a walkie-talkie in front of a Free Syrian Army police station in Aleppo January 3, 2015. This battalion, controlled by the Free Syrian Army, provides aid and security in addition to being a full military unit. The women who make up this force not only operate as fighters on the Old Aleppo frontline, but are also in charge of two field hospitals for injured fighters and a police station for women detainees. The text on the wall reads in Arabic, "Revolutionary Military Police". Picture taken January 3, 2015. REUTERS/Abdalrhman Ismail (SYRIA - Tags: POLITICS CIVIL UNREST CONFLICT) 

Ali Badran, a 14-year-old Syrian, uses a walkie-talkie at an observation post to locate the positions of forces loyal to Syria's President Bashar al-Assad and monitor their movements in Jabal al-Zawiya in the Idlib countryside September 7, 2014. Badran quit school two years ago to become an observer after his father taught him the relevant skills. Picture taken September 7, 2014. REUTERS/Khalil Ashawi (SYRIA - Tags: POLITICS CIVIL UNREST CONFLICT TPX IMAGES OF THE DAY) 

An Islamist Syrian rebel group Jabhat al-Nusra fighter talks on a walkie-talkie while carrying his weapon on Al-Khazan frontline of Khan Sheikhoun, northern Idlib province May 17, 2014. REUTERS/Hamid Khatib (SYRIA - Tags: CIVIL UNREST MILITARY POLITICS CONFLICT) 

A Search and Rescue member communicates on his walkie talkie inside a truck as Mount Sinabung volcano spews ash at Berastepu village in Karo district, Indonesia's North Sumatra province, January 8, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY) 

A female member of the Kurdish People's Protection Units (YPG) holds a walkie talkie as she stands along a street in the west of the city of Ras al-Ain, after capturing it from Islamist rebels November 5, 2013. Redur Xelil, spokesman for the armed wing of the Syrian Kurdish Democratic Union Party (PYD), said Kurdish militias had seized the city of Ras al-Ain and all its surrounding villages. Syrian Kurdish fighters have captured more territory from Islamist rebels in northeastern Syria, a Kurdish militant group said on Monday, tightening their grip on an area where they have been setting up autonomous rule. Picture taken November 5, 2013. REUTERS/Stringer (SYRIA - Tags: POLITICS CIVIL UNREST CONFLICT) 

A Palestinian militant drinks juice during an anti-Israeli rally organized by Islamic Jihad movement in Rafah in the southern Gaza Strip October 24, 2013. REUTERS/Suhaib Salem (GAZA - Tags: POLITICS CIVIL UNREST) 

A Free Syrian army fighter uses a walkie-talkie in Suleiman Al-Halabi neighbourhood of Aleppo, September 14, 2013. REUTERS/Hamid Khatib (SYRIA - Tags: POLITICS CIVIL UNREST CONFLICT) 

Free Syrian Army fighters sit at their guard post in the eastern Hama countryside September 13, 2013. REUTERS/Molhem Barakat (SYRIA - Tags: POLITICS CIVIL UNREST) 

A Free Syrian Army fighter offers a child a walkie-talkie to communicate with fellow fighters, as they sit along a street in Deir al-Zor August 19, 2013. Picture taken August 19, 2013. REUTERS/Khalil Ashawi (SYRIA - Tags: CONFLICT CIVIL UNREST BUSINESS TELECOMS) 

A Free Syrian Army fighter uses a walkie-talkie to talk with a fellow fighter as he watches a surveillance monitor in Deir al-Zor July 25, 2013. Picture taken July 25, 2013. REUTERS/Khalil Ashawi (SYRIA - Tags: CONFLICT POLITICS CIVIL UNREST) 

A Free Syrian Army fighter communicates using a walkie-talkie in the Mouazafeen neighbourhood in Deir al-Zor, June 14, 2013. Picture taken June 14, 2013. REUTERS/Khalil Ashawi (SYRIA - Tags: CIVIL UNREST CONFLICT) 

Members of the Free Syrian army observe surveillance monitors in the Khaldiyeh district in central Homs May 9, 2013. REUTERS/Yazan Homsy (SYRIA - Tags: CONFLICT) 

A Palestinian militant of the Democratic Front for the Liberation of Palestine (DFLP) inspects a training base after it was hit by an Israeli air strike in Rafah in the southern Gaza Strip April 28, 2013 .An Israeli aircraft hit a site belonging to Palestinian militants in the Gaza Strip on Sunday in response to a rocket that militants fired from the territory into southern Israel, the Israeli military said. REUTERS/Ibraheem Abu Mustafa (GAZA - Tags: POLITICS CIVIL UNREST) 

U.S. Border Patrol agent Manny Villalobos looks out from inside his ATV helmet during his patrol along the international border between Mexico and the United States near San Diego, California March 26, 2013. REUTERS/Mike Blake (UNITED STATES - Tags: POLITICS CRIME LAW) 

U.S. Customs and Border Patrol agent David Faatoalia wears a radio on his chest as he patrols along the international border between Mexico and the United States near San Diego, California, March 26, 2013. Picture taken March 26, 2013. REUTERS/Mike Blake (UNITED STATES - Tags: POLITICS SOCIETY IMMIGRATION CRIME LAW) 

A man with a sign on his back, which reads 'democracy', is questioned by police near the Great Hall of People in Tiananmen Square, central Beijing March 2, 2013, before the upcoming National People's Congress (NPC). REUTERS/Carlos Barria (CHINA - Tags: POLITICS CIVIL UNREST) 

A policeman patrols a beach on the outskirts of Havana September 1, 2012. Cuba's beaches are an attraction for tourists the world over, whether they are foreigners paying thousands of dollars to reach them, or Cubans paying as little as five dollars for a three-day vacation in a seaside cabin. Picture taken September 1, 2012. REUTERS/Desmond Boylan (CUBA - Tags: SOCIETY POLITICS TRAVEL) 

Firefighter Alex Abols monitors fire on the north flank of the Fontenelle Fire outside Big Piney, Wyoming, July 4, 2012. Over 800 firefighters are working 15 hour shifts battling the fire that has exceeded 56,000 acres, according to fire information services. Record fire danger and long stretches of the red flag warning days have made it challenging to control. The crews are working and sleeping in close proximity to the fire in an effort to contain it. The blaze, burning in dead and thick stands of timber, started on June 24 and is currently 15 percent contained. Recently firefighting crews from as far away as Alaska have arrived to fight it. Picture taken July 4, 2012. REUTERS/Jim Urquhart (UNITED STATES - Tags: ENVIRONMENT DISASTER) 

An Angeles National Forest firefighter reports information about a brush fire spread out over an area of more than 500 acres (2 square km) at Los Padres National Forest in California June 16, 2012.
The fire started on Saturday afternoon in the hills of the forest between the cities of Frazier Park and Ojai. No structures have been burned and the fire-fighters have no containment on the blaze at this time. Picture taken June 16, 2012. REUTERS/Gene Blevins (UNITED STATES - Tags: DISASTER ENVIRONMENT) 

A firefighter talks on his remote radio as smoke from the Gladiator Fire is visible in Cleator, Arizona May 17, 2012. Crews with hand tools battled to contain wind-whipped Arizona wildfires on Wednesday that have raced across more than 30 square miles of parched ponderosa forest, brush and grassland, consuming several buildings and threatening a small town. REUTERS/Joshua Lott (UNITED STATES - Tags: DISASTER ENVIRONMENT) 

Policemen detain a protester during an anti-austerity rally at central Syntagma square in Athens February 17, 2012. Greece appears to be closing in on a new international rescue package despite unresolved doubts among euro zone partners about how fast it will manage to bring its debt down. REUTERS/John Kolesidis (GREECE - Tags: BUSINESS POLITICS CIVIL UNREST) 

A worker checks the water level in a lake near the hydropower plants in Trebinje, 300 km (186 miles) south of Sarajevo, December 15, 2011. Bosnia's second-largest power utility Elektroprivreda RS (EPRS) provides power to the Serb-dominated parts of Bosnia, while the country's other two utilities Sarajevo-based Elektroprivreda BiH (EPBiH) and Mostar-based EPHZHB, operate in Bosnia's other autonomous region, the Muslim-Croat Federation. EPRS operates three big and several small hydropower plants with a combined installed capacity of 617 MW and two-coal-fired plants. It produced 2,882 GWh of electricity in the first half of 2011, 3.5 percent above its target on the back of its substantial hydropower capacity but drought in the second half of the year has hurt its output. Elektroprivreda RS has been importing 1.5 GWh of power per day to meet local demand and was forced to cancel agreed power exports. REUTERS/Dado Ruvic (BOSNIA AND HERZEGOVINA - Tags: ENERGY ENVIRONMENT) 

An Afghan National Army soldier looks out of his bunker at Observation Post Mace in eastern Afghanistan's Kunar province near the border with Pakistan August 28, 2011. REUTERS/Nikola Solic (AFGHANISTAN - Tags: MILITARY CONFLICT POLITICS) 

A student runs after a police officer to beg for his college fee during a protest against what students say is a fee hike of 182 colleges affiliated with the state Punjab University, in the northern Indian city of Chandigarh July 8, 2011. REUTERS/Ajay Verma (INDIA - Tags: CIVIL UNREST EDUCATION) 

A Buddhists monk uses a radio as he gives instructions to others arriving for a prayer during Vesak Day, an annual celebration of Buddha's birth, enlightenment and death, at Wat Dharmmakaya in Pathum Thani province, on the outskirts of Bangkok May 17, 2011. REUTERS/Damir Sagolj (THAILAND - Tags: RELIGION SOCIETY) 

A labourer works in a sewer in downtown Shanghai May 11, 2011. China's census results show the world's second-biggest economy is nearing a demographic watershed that will auger wage rises, higher inflation and relatively lower growth, a prominent government economist said in comments published last week. REUTERS/Carlos Barria (CHINA - Tags: BUSINESS EMPLOYMENT) 

Iraqi traffic policewoman Alya Hussein Qassim, 28, uses a radio transceiver as she keeps watch along a main street in the southern city of Basra, 420 km (260 miles) southeast of Baghdad April 2, 2011. Alya is the first traffic policewoman in the conservative society of Basra city that witnessed a wave of women killings in 2007. Picture taken April 2, 2011. REUTERS/Atef Hassan (IRAQ - Tags: EMPLOYMENT BUSINESS SOCIETY) 

Equipment packed for an assignment to the Arctic can be seen in the living room of Reuters photographer Lucas Jackson in New York March 16, 2011. REUTERS/Lucas Jackson (UNITED STATES - Tags: ENVIRONMENT MEDIA) 

A rescue worker uses a two-way radio transceiver during heavy snowfall at a factory area devastated by an earthquake and tsunami in Sendai, northern Japan March 16, 2011. REUTERS/Kim Kyung-Hoon (JAPAN - Tags: DISASTER SOCIETY) 

Egyptian Army special forces personnel stand guard beside a golden funerary mask of King Tutankhamun at the Egyptian Museum in Cairo February 16, 2011. Egypt's Antiquities Ministry has recovered some of the national treasures that went missing from the Egyptian Museum during an uprising which unseated Hosni Mubarak. The Ministry has found two of the eight missing artifacts outside the museum between a government building that got burned and the gift shop and will continue the search, Egypt's Minister of Antiquities Zahi Hawass told Reuters on Monday. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST POLITICS MILITARY SOCIETY IMAGES OF THE DAY) 

Police officers, one with a face injury, stand outside the Conservative Party headquarters building during a protest in central London November 10, 2010. A group of protesters against higher university tuition fees broke into the headquarters of Britain's governing Conservative party on Wednesday, smashing the glass reception area and streaming up onto the roof. REUTERS/Paul Hackett (BRITAIN - Tags: CIVIL UNREST POLITICS EDUCATION) 

A security official looks at a screen displaying X-ray screened parcels in Turkish Post's (PTT) postal logistic centre at the Ataturk International airport in Istanbul November 6, 2010. REUTERS/Murad Sezer (TURKEY - Tags: TRANSPORT) 

An armed policeman patrols in front of the Houses of Parliament in London October 18, 2010. Cyber attacks, terrorism, inter-state conflict and natural hazards are the top threats to British security, officials said Monday, a day before a major military review due to include deep spending cuts. REUTERS/Luke MacGregor (BRITAIN - Tags: CRIME LAW POLITICS) 

An Iraqi policeman distributes the holy Koran between security checkpoints at al-Firdous square in Baghdad September 9, 2010. Iraqi Prime Minister Nuri al-Maliki urged the United States on Thursday to prevent the American pastor of an obscure Christian church from burning copies of the Koran in commemoration of Sep. 11 attacks. REUTERS/Mohammed Ameen (IRAQ - Tags: MILITARY RELIGION) 

One of several protesters from the Scottish Afghan Society stands outside the U.S. consulate in Edinburgh, Scotland September 9, 2010. Members of the society gathered outside the consulate to protest about the proposed burning of the Koran by Florida pastor Terry Jones on the anniversary of the 9/11 terrorist attacks. REUTERS/David Moir (BRITAIN - Tags: RELIGION POLITICS) 

A Dominican soldier listens to instructions by radio during the official visit of Colombia's President-elect Juan Manuel Santos to the national palace in Santo Domingo July 29, 2010. REUTERS/Eduardo Munoz (DOMINICAN REPUBLIC - Tags: POLITICS MILITARY) 

A South Korean soldier uses a walkie-talkie as he stands guard on the south side of the truce village of Panmunjom in the demilitarised zone separating the two Koreas in Paju, north of Seoul April 28, 2010, as a group of media people visit during a media tour organised by the U.S. Forces Korea. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY POLITICS) 

An army soldier gives an order to soldiers as they charge toward anti-government "red-shirt" protesters who seized an army truck and blocked a main road leading into Bangkok, about 45km (18 miles) north of the city April 26, 2010. A grenade attack on the home of a senior Thai politician and acts of defiance in the provinces deepened fears on Monday over civil conflict after the prime minister rejected demands by anti-government protesters. Protesters fortified a sprawling encampment in Bangkok's main shopping district and urged supporters in northern regions to block convoys of police and soldiers from travelling to the capital, adding to a growing sense of lawlessness. REUTERS/Jerry Lampen (THAILAND - Tags: POLITICS CIVIL UNREST MILITARY) 

A security walks in front of the Google China headquarters in Beijing January 13, 2010. Google Inc said it may pull out of China because it is no longer willing to accept censorship of its search results, in a surprise retreat from the world's largest Internet market by users. REUTERS/Jason Lee(CHINA - Tags: BUSINESS) 

Staff at the U.S. Transporation Security Administration (TSA) Systems Integration Facility, one playing the role of a airline passenger (L) demonstrate the use of Millimeter Wave technology for passenger security screening in Washington, December 30, 2009. The TSA demonstrated two advanced imaging technologies that are used to safely screen passengers for metallic and non-metallic threats including weapons, explosives and other objects concealed under layers of clothing without physical contact. REUTERS/Jason Reed (UNITED STATES - Tags: SOCIETY TRANSPORT SCI TECH) 

A German Bundeswehr army soldier of the 4th company, 391 mechanised infantry battalion, part of the International Security Assistance Force (ISAF) uses his radio after coming under attack during a mission to reconstruct a bridge which was destroyed by insurgents in Chahar Dara in the outskirts of Kunduz, December 14, 2009. German soldiers were attacked by mortars and gave response fire together with Aghan National Police (ANP) for more than one hour. REUTERS/Fabrizio Bensch (AFGHANISTAN - Tags: MILITARY CONFLICT)