BEIRUT — Syrian rebels said Tuesday that they reached a cease-fire deal with Moscow to evacuate civilians and fighters from eastern Aleppo, after the U.N. and opposition activists reported possible mass killings by government forces closing in on the rebels' last enclave.
There was no immediate comment from Damascus or Moscow on the agreement, which would effectively cede the remainder of Syria's largest city to President Bashar Assad's forces after months of heavy fighting and a crippling siege.
Osama Abu Zayd, a Turkey-based legal adviser for an umbrella group of rebel factions known as the Free Syrian Army, said the cease-fire went into effect Tuesday evening and that the first batch will begin evacuating within hours.
Yasser al-Youssef, a spokesman for the Nour el-Din el-Zinki rebel group, confirmed the cease-fire and said the goal is to evacuate civilians and rebels from besieged areas.
It was not immediately clear whether the hostilities had ceased in Aleppo. The opposition-run Syrian Observatory for Human Rights said shelling was continuing.
World leaders and aid agencies issued dramatic appeals on behalf of trapped residents earlier Tuesday, and the U.N. human rights office said that pro-government forces reportedly killed 82 civilians "on the spot" as they closed in on remaining rebel districts.
That and other reports of mass killings, which could not be independently confirmed, reinforce fears of atrocities in eastern Aleppo in the final hours of the battle for the city, which has been split between rebel and government control since 2012.
Several residents and opposition activists have told The Associated Press that government forces carried out summary killings of rebels in the streets in neighborhoods captured on Monday, but the Syrian military flatly denied the claims, saying such allegations were "a desperate attempt" to try gain international sympathy.
None of the residents reached by AP witnessed the alleged killings, and their accounts reflected the deepening chaos. Mohammed Abu Rajab, the administrator of the last remaining clinic in rebel-held parts of the city, said people who were killed or wounded are being left in the streets.
Aref al-Aref, a nurse and activist in eastern Aleppo, said civilians had taken cover in a medical center after its staff evacuated two days earlier. He said the army killed them, but pressed for details, said he only heard it from others.
Monther Etaky, a resident of eastern Aleppo, said he also heard reports of summary killings and knows of three families who were reportedly killed.
The U.N.'s children agency said Tuesday that there could be more than 100 unaccompanied children trapped in building under fire in eastern Aleppo, citing a report from an unnamed doctor in the city. Regional director Geert Cappalaere said UNICEF is concerned over the unverified reports of "extrajudicial killings of civilians, including children."
The U.N.'s human rights office said it has received reports of pro-government forces killing at least 82 civilians in four neighborhoods of the rapidly-shrinking rebel enclave, including 11 women and 13 children.
Spokesman Rupert Colville said the reports recount pro-government forces entering homes and killing some civilians "on the spot." He told reporters in Geneva that the reports came in late Monday evening and that he doesn't know exactly when the killings took place.
U.N. Secretary-General Ban Ki-moon said in a statement late Monday that he is alarmed over reports of "atrocities" against a large number of civilians, including women and children, in the past hours in Aleppo. While stressing that the United Nations is not able to independently verify the reports, the U.N. chief said he conveyed his grave concern to the relevant parties.
A press release by the U.N. human rights office in Geneva said that multiple sources reported that tens of civilians were shot dead on Monday in al-Ahrar Square in Kallaseh neighborhood, and also in Bustan al-Qasr, by government forces and their allies, including an Iraqi Shiite militia known as al-Nujabaa.
The dramatic appeals for sparing civilian lives came a day after the Syrian military announced it now holds 99 percent of the former rebel neighborhoods of Aleppo, signaling an impending end to the rebels' four-year hold over parts of the city.
Retaking Aleppo would be Assad's biggest victory yet in the civil war. But a government win in Aleppo does not end the conflict — significant parts of Syria are still outside government control and huge swaths of the country are a devastated wasteland. More than a quarter of a million people have been killed since the conflict began in 2011 with peaceful protests against the Assad family's four-decade rule.
Rami Abdurrahman of the Britain-based Observatory said hundreds of bodies are still under the rubble.
The International Committee of the Red Cross urged all those fighting in Aleppo to spare civilian lives. It said that thousands of people in eastern Aleppo with no part in the violence "have literally nowhere safe to run."
Russia, which has been a key ally of Assad, said the rebels are holding out in a neighborhood roughly the size of 3 square kilometers (1.16 square miles).
Earlier Tuesday, French President Francois Hollande pressed for Russia to facilitate humanitarian aid to civilians trapped in rebel-held parts of the city, saying the Aleppo "humanitarian situation ... is unacceptable."
He said the Russians "will be responsible for a situation that they helped create if they do nothing to allow access for humanitarian aid."
Russia said it was fed up with calls for a halt to the fighting, singling out the Obama administration, which has spent months trying to negotiate a cease-fire.
"We are tired of hearing this whining from our American colleagues in the current administration that we need to immediately halt military action," Foreign Minister Sergey Lavrov told journalists during a visit to Serbia.
Keaten reported from Geneva. Associated Press writers Sarah El Deeb and Zeina Karam contributed from Beirut.