Doctors treat an injured civilian in a field hospital after what activists said was shelling by forces of Syria's President Bashar al-Assad in the Douma neighbourhood of Damascus, Eastern Ghouta, Syria in this November 19, 2015 file photo. Douma in Syria, an area controlled by rebels fighting to topple President Bashar al-Assad, has been shelled continuously for the past three years. The injured are taken to basements and shelters transformed into field hospitals run by medical staff who have stayed in the battered neighbourhood of Damascus. (Photo by Bassam Khabieh/Reuters)





An injured girl is transported in an ambulance after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad, in the Douma neighborhood of Damascus, Syria November 29, 2015. (Photo by Bassam Khabieh/Reuters)





A school bag that belongs to an injured student lies on the floor inside a field hospital after after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





Medics rest after after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





A medic tests patients' blood inside a field hospital in the Douma neighborhood of Damascus, Syria December 5, 2015. (Photo by Bassam Khabieh/Reuters)





A baby lies inside a neonatal unit in a field hospital in the Douma neighborhood of Damascus, Syria December 8, 2015. The baby was born after a cesarean surgery after his mother died from shelling by what activists said was forces loyal to Syria's president Bashar al-Assad in the Douma neighborhood of Damascus, Syria. (Photo by Bassam Khabieh/Reuters)





An injured boy who is undergoing surgery, after he was injured in what activists said was an airstrike by forces loyal to Syria's president Bashar al-Assad, rests inside a field hospital in the Douma neighborhood of Damascus, Syria December 5, 2015. (Photo by Bassam Khabieh/Reuters)





An injured girl reacts, after she was injured in what activists said was an airstrike by forces loyal to Syria's president Bashar al-Assad, inside a field hospital in the Douma neighborhood of Damascus, Syria December 5, 2015. (Photo by Bassam Khabieh/Reuters)





An injured child sits inside a field hospital, after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad, in the Douma neighborhood of Damascus, Syria November 29, 2015. (Photo by Bassam Khabieh/Reuters)





Medics treat an injured child inside a field hospital, after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad, in the Douma neighborhood of Damascus, Syria November 29, 2015. (Photo by Bassam Khabieh/Reuters)





An injured child holds coins in his hand as he lies on a bed inside a field hospital, after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad, in the Douma neighborhood of Damascus, Syria November 29, 2015. (Photo by Bassam Khabieh/Reuters)





A view shows the damage inside a nursery for newborn babies after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





Medical tubing is pictured outside a damaged newborn nursery after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





A medic treats an injured girl inside a field hospital after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





An injured man waits to receive treatment inside a field hospital after after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





Medics treat an injured man inside a field hospital after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





Blood drops are seen on the stairway of a field hospital, after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad in the Douma neighborhood of Damascus, Syria December 2, 2015. (Photo by Bassam Khabieh/Reuters)





A tray of food left by medics lies on the floor inside a field hospital, after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





Doctors pray inside a field hospital in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





An injured boy receives treatment inside a field hospital, after what activists said was shelling by forces by Syria's President Bashar al-Assad, in the Douma neighborhood of Damascus, Syria December 2, 2015. (Photo by Bassam Khabieh/Reuters)





A man sits inside a medical supply room inside a field hospital after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad in the Douma neighborhood of Damascus, Syria December 2, 2015. (Photo by Bassam Khabieh/Reuters)





A man, injured in what activists said was an airstrike by forces loyal to Syria's president Bashar al-Assad, rests inside a field hospital in the Douma neighborhood of Damascus, Syria December 6, 2015. (Photo by Bassam Khabieh/Reuters)





An injured man sits inside a field hospital after what activists said was shelling by forces by Syria's President Bashar al-Assad in the Douma neighborhood of Damascus, Syria December 2, 2015. (Photo by Bassam Khabieh/Reuters)





An injured man rests inside a field hospital, after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad in the Douma neighborhood of Damascus, Syria December 2, 2015. (Photo by Bassam Khabieh/Reuters)





A man, injured in what activists said was an airstrike by forces loyal to Syria's president Bashar al-Assad, lies in a field hospital in the Douma neighborhood of Damascus, Syria December 6, 2015. (Photo by Bassam Khabieh/Reuters)





An injured student rests inside a field hospital after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)





A woman carries an injured baby born inside a field hospital after what activists said were air and missile strikes in the Douma neighborhood of Damascus, Syria December 13, 2015. (Photo by Bassam Khabieh/Reuters)