The operation to evacuate civilians from Aleppo was suspended on Friday after rebel fighters in Syria’s Idlib province refused to simultaneously transport 400 wounded people from the two pro-government villages of Fua and Kefraya, according to reports. However, an al-Qaeeda affiliated Jabhat Fateh al-Sham member later told The Guardian that they had agreed to the deal.

At least 50,000 civilians are still trapped in war-torn Aleppo, though around 8,000 have been evacuated so far, the United Nations said on Friday. A convoy of ambulances and buses with nearly 1,000 people drove out of the city, which has been bombarded for many months by Syrian government forces fighting rebels, reported Reuters. Two more convoys of 15 buses each left Aleppo on Friday.

Civilians evacuated from Syria’s largest city are being taken to the northern province of Idlib, an opposition bastion, as per the ceasefire agreement. “If there is no political agreement and a ceasefire, Idlib will become the next Aleppo,” UN Special Envoy for Syria Staffan de Mistura said.

After the evacuation plan failed to take off on Wednesday and clashes began afresh, a second ceasefire agreement was announced on Thursday. The operation was reportedly stalled after Iran imposed new conditions. Syrian President Bashar al-Assad hailed the liberation of Aleppo after many years of fighting, calling it a historic moment, reported BBC.

US Secretary of State John Kerry on Thursday said the Syrian government was carrying out “nothing short of a massacre” in Aleppo. “The only remaining question is whether the Syrian regime, with Russia’s support, is willing to go to Geneva prepared to negotiate constructively, and whether or not they’re willing to stop this slaughter of their own people,” Kerry had said.