The evacuation of civilians from eastern Aleppo was directly linked to the ongoing conversations between President Recep Tayyip Erdoğan and his Russian counterpart Vladimir Putin, the Russian president's spokesman Dmitry Peskov said Thursday.
On Tuesday evening, regime forces and opposition groups agreed to a Turkey-brokered cease-fire deal with a view to evacuating civilians from the eastern part of the city.
The Turkish and Russian presidents spoke over the phone about Aleppo on Wednesday as they discussed the human tragedy in Aleppo and bilateral relations between Turkey and Russia, sources said.
The two leaders agreed the partial cease-fire deal should be implemented completely and no violations should take place, the source added.
The first evacuation convoy, carrying sick and injured people, left eastern Aleppo on early Thursday morning, however, it was attacked by militia groups backed by Iran, as well as regime forces.
According to local reports, four people were killed and several were injured when Iran-backed Shiite militias opened fire on the convoy.
The convoy of 20 buses was carrying at least 200 injured people with over 50 in critical condition, according to an Anadolu Agency reporter at the scene of the attack.
After the cease-fire was violated, Turkish Foreign Minister Mevlüt Çavuşoğlu spoke with his Iranian counterpart Javad Zarif two times over the phone.
Violence escalated in Aleppo city on Monday when Syrian regime forces advanced into opposition-held parts of eastern parts of the city following a five-month siege and persistent aerial bombardment.
The Russian-backed regime had been trying to reestablish control over parts of Aleppo captured four years ago by armed opposition groups.
Syria has been locked in a devastating civil war since early 2011 when the regime cracked down on pro-democracy protests, which had erupted as part of the Arab Spring uprisings, with unexpected ferocity.
Since then, hundreds of thousands of people are believed to have been killed by the conflict and millions more displaced.