People gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily TPX IMAGES OF THE DAY

People gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily 

People gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily 

People gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily 

Iraqi security forces and people gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily 

Iraqi security forces and people gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily 

Iraqi security forces and people gather at the site of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 17, 2016. REUTERS/Khalid al Mousily 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili TPX IMAGES OF THE DAY

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

A member of Iraqi security forces inspects the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

A woman reacts at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili 

People gather at the scene of a car bomb attack in Baghdad's mainly Shi'ite district of Sadr City, Iraq, May 11, 2016. REUTERS/Wissm al-Okili TPX IMAGES OF THE DAY 

A member of the self-proclaimed Donetsk People's Republic forces stands near the wreckage of a car destroyed in explosions in the rebel-controlled village of Yelenovka outside Donetsk, Ukraine, April 27, 2016. REUTERS/Alexander Ermochenko TPX IMAGES OF THE DAY

Smoke rises at the site of a car bomb attack in Baghdad al-Jadida, Iraq April 25, 2016. REUTERS/Ahmed Saad 

Civilians gather at the site of a car bomb attack in Baghdad al-Jadida, Iraq April 25, 2016. REUTERS/Ahmed Saad 

Smoke rises at the site of a car bomb attack in Baghdad al-Jadida, Iraq April 25, 2016. REUTERS/Ahmed Saad 

Iraqi security forces and civilians gather at the site of a car bomb attack in Baghdad al-Jadida, Iraq April 25, 2016. REUTERS/Ahmed Saad 

Workers clean a street at the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki 

A picture of Syria's President Bashar al-Assad is seen inside a checkpoint at the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki 

A view shows the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki 

Patients that were evacuated from two rebel-besieged towns of Foua and Kefraya in the northwestern province of Idlib, are seen inside a hospital that was struck by an explosion on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. In the background a poster depicting Syria's President Bashar al-Assad and Lebanon's Hezbollah leader Sayyed Hassan Nasrallah. REUTERS/Omar Sanadiki 

A picture of Syria's President Bashar al-Assad is seen inside a checkpoint at the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki TPX IMAGES OF THE DAY

A civilian looks out from a window of a damaged building at the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki TPX IMAGES OF THE DAY

Workers clean a street at the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki TPX IMAGES OF THE DAY

A man on a crane works at the site of a car bomb on the outskirts of the Sayeda Zeinab district south of Damascus, Syria, April 25, 2016. REUTERS/Omar Sanadiki 

People inspect the damage after a car bomb exploded and targeted a religious center in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria April 5, 2016. REUTERS/Khalil Ashawi 

People inspect the damage after a car bomb exploded and targeted a religious center in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria April 5, 2016. REUTERS/Khalil Ashawi 

People inspect the damage after a car bomb exploded and targeted a religious center in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria April 5, 2016. REUTERS/Khalil Ashawi 

People inspect the damage after a car bomb exploded and targeted a religious center in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria April 5, 2016. REUTERS/Khalil Ashawi 

People inspect the damage after a car bomb exploded and targeted a religious center in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria April 5, 2016. REUTERS/Khalil Ashawi TPX IMAGES OF THE DAY

Residents carry the body of a victim of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

A fireman stands at the scene of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

An Iraqi man walks at the scene of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

A fireman stands at the scene of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

A fireman hoses down a vehicle at the scene of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

Iraqi security forces with people gather at the site of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

A fire truck is seen at the site of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani 

A member of the Iraqi security forces walks at the site of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani TPX IMAGES OF THE DAY

Iraqi security forces with people gather at the site of a car bomb attack in Basra April 4, 2016. REUTERS/Essam Al-Sudani

Somali policemen look at the wreckage of a car at the scene of an explosion following an attack in Somalia's capital Mogadishu, March 9, 2016. Islamist group al Shabaab said it fought off an attack on one of its bases in southern Somalia early on Wednesday that was launched by foreign commandos who flew in on two helicopters, leaving one al Shabaab fighter dead in the gun battle. REUTERS/Feisal Omar 

A Somali woman walks past the scene of an explosion following an attack in Somalia's capital Mogadishu, March 9, 2016. Islamist group al Shabaab said it fought off an attack on one of its bases in southern Somalia early on Wednesday that was launched by foreign commandos who flew in on two helicopters, leaving one al Shabaab fighter dead in the gun battle. REUTERS/Feisal Omar 

A Somali policeman walks at the scene of an explosion following an attack in Somalia's capital Mogadishu, March 9, 2016. Islamist group al Shabaab said it fought off an attack on one of its bases in southern Somalia early on Wednesday that was launched by foreign commandos who flew in on two helicopters, leaving one al Shabaab fighter dead in the gun battle. REUTERS/Feisal Omar TPX IMAGES OF THE DAY 

Somali policemen gather near the wreckage of a car at the scene of an explosion following an attack in Somalia's capital Mogadishu, March 9, 2016. Islamist group al Shabaab said it fought off an attack on one of its bases in southern Somalia early on Wednesday that was launched by foreign commandos who flew in on two helicopters, leaving one al Shabaab fighter dead in the gun battle. REUTERS/Feisal Omar 

Residents gather at the site of a car bomb attack at a checkpoint in the city of Hilla, south of Baghdad, March 6, 2016. REUTERS/Alaa Al-Marjani

A Somali man injured in a night car bomb attack near a hotel in Hamarweyne district sits along a sidewalk near the scene in capital Mogadishu, Somalia February 26, 2016. REUTERS/Feisal Omar 

A view shows a section of collapsed walls of a building destroyed after a car bomb attack in Hamarweyne district in capital Mogadishu, Somalia February 26, 2016. REUTERS/Feisal Omar 

A car suspected by the Somali police to have been used in a bomb attack burns along a street near a hotel in Hamarweyne district in capital Mogadishu, Somalia February 26, 2016. REUTERS/Feisal Omar TPX IMAGES OF THE DAY

Senegalese officers gather near an exploded vehicle at a military range during the U.S.-led "Flintlock" training exercises for African militaries, in Thies, Senegal February 18, 2016. REUTERS/Emma Farge 

A family member of Wednesday's car bombing victims is comforted by the others as he mourns outside a morgue in Ankara, Turkey, February 18, 2016. Twenty-eight people were killed and dozens wounded in Turkey's capital Ankara on Wednesday when a car laden with explosives detonated next to military buses near the armed forces' headquarters, parliament and other government buildings. REUTERS/Umit Bektas 

A family member of Wednesday's car bombing victims mourns outside a morgue in Ankara, Turkey, February 18, 2016. Twenty-eight people were killed and dozens wounded in Turkey's capital Ankara on Wednesday when a car laden with explosives detonated next to military buses near the armed forces' headquarters, parliament and other government buildings. REUTERS/Umit Bektas