Russia declared on Tuesday that the four-year battle over Aleppo, Syria’s largest city, was over, as the last remaining rebel fighters agreed to turn over their territory to the Syrian government. While pro-government forces were moving in, United Nations officials said they were receiving multiple reports of execution-style killings. Five buses will head into the enclave in the eastern section of the city to pick up the survivors around 5 a.m. Wednesday local time, a source said.

It was not immediately clear what weapons the fighters will be allowed to take with them, they said.

“My brothers, cease fire in all neighborhoods of besieged Aleppo city, total ceasefire but all units be prepared in case of any breach of the cease-fire,” Alfarouq, the leader of the Ahrar ash-Sham rebel group, who negotiated the deal, declared in a statement. “Now it is a ceasefire but it’s still in the beginning (and) might fail. So cease fire, but stay on high alert. God bless you.”

Several residents said they had lost contact with relatives in those same areas, and a monitoring group, the Syrian Observatory for Human Rights, said the number of men forced to join the army upon fleeing to government areas had reached 6,000. And with no way to treat the wounded, bodies were piling up on the streets of the shrinking rebel territory.

But then came the deal, and the shelling quieted down. Russia, Turkey and Syrian rebel groups announced that they had agreed to evacuate all of the remaining fighters to rebel-held territory, with civilians free to join them or move to government-held areas, leaving the whole city of Aleppo in government hands.

Eleven women and 13 children were among those killed in four different neighborhoods late Monday, Colville told a news briefing, adding that there could be “many more.”

“The reports we had are of people being shot in the street trying to flee and shot in their homes.”

Jens Laerke, U.N. humanitarian spokesman said that it looked like “a complete meltdown of humanity in Aleppo.”

U.N. agency UNICEF said “many children, possibly more than 100, unaccompanied or separated from their families, are trapped in a building, under heavy attack in east Aleppo,” citing reports form a doctor on the scene.

Arab media reported that scores of civilians were burned alive by regime forces, although this was not confirmed by observers at the Aleppo Media Center or the U.K.-based Syria Observatory for Human Rights.

Charles Lister, a Syria expert and senior fellow at the Middle East Institute, said there were “truly shocking stories from Aleppo including husbands and wives taking each other’s lives in family suicides” and that hundreds may have died during Monday’s fighting.