A survivor sits on rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
A survivor sits on the rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
A survivor reacts at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
A survivor reacts at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
Girls stand as they look at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
Girls stand as they look at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
Women walk near a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
Women walk near a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CONFLICT)
People search for survivors under the rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
People search for survivors under the rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
A boy cries as he stands amid rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
A boy cries as he stands amid rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CONFLICT)
People search for survivors under rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
People search for survivors under rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
A man runs as he carries a child at a site hit by what activists said was a barrel bomb in Aleppo's al-Sakhour district
A man runs as he carries a child at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
Children walk at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
Children walk at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)
A woman holds a boy as she sits at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district
A woman holds a boy as she sits at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's al-Sakhour district March 6, 2014. REUTERS/Hosam Katan (SYRIA - Tags: POLITICS CIVIL UNREST)