The United Nations Under-Secretary-General for Humanitarian Affairs Stephen O'Brien said Tuesday that more than 100 civilians had fallen victim to anti-Daesh airstrikes in Syria, noting that the conflict continues to devastate civilians.

Speaking at a U.N. Security Council Meeting, O'Brien said that children had been forcibly detained, tortured, subjected to sexual violence, forcibly recruited and, in some cases, executed in Syria, while more than 100 civilians were killed by the U.S.-led anti-Daesh coalition, notably in Raqqa and Deir ez-Zor.

He also stated that the Syrian regime refuses to aid the needy and pushes people in besieged cities to choose between starvation and death or fleeing to locations that are just as unsafe, using civilian suffering as "a tactic of war."

"These are evacuations that have followed years of intense airstrikes, shelling and sniping," O'Brien said. "The tactics are all too obvious: make life intolerable and make death likely."

O'Brien added that just in last week 30 women and children had been injured in an attack by Daesh in Deir ez-Zor.

"There needs to be accountability for these actions, for these ‘starve and surrender tactics' a monstrous form of cruelty to impose upon a civilian population," he said.

He highlighted that nearly 7 million children lived in poverty and 1.75 million were out of school, noting that one in three schools, 7,400 in total, had been damaged or destroyed in Syria.

He also reminded that meanwhile, outside Syria, hundreds of thousands of Syrian children had become stateless, abandoned but for the generosity of Lebanon, Jordan, Iraq, Turkey and Egypt.