The ceasefire deal in Aleppo, Syria does not appear to be holding as efforts to evacuate rebels and civilians have been hampered.

According to dpa, quoting pro-Syrian government sources, buses meant to evacuation missions have returned empty, signalling the ceasefire deal has failed.

"The government forces have withdrawn all buses that waited at al-Haj Bridge east of Aleppo for evacuation after the agreement faltered," said the source.

"Delay in evacuating the insurgents, their families and other civilians is due to differences among leaders of insurgents," the source added, on condition of anonymity.

The Syrian opposition has accused the regime forces of shelling the rebel enclave in eastern Aleppo, dooming a Russian-Turkish ceasefire pact in the embattled area.

Turkish President Tayyip Erdogan has accused Syrian government forces of breaking a ceasefire deal in Aleppo, but said Turkey is still making efforts to create a corridor to evacuate people from the war torn city.

Erdogan said he would speak later by phone with Russian President Vladimir Putin about the situation in Aleppo, which he described as "very fragile". He was addressing a group of local administrators in Ankara, in comments broadcast live, according to Reuters.

Erdogan also said preparations were complete for evacuees from Aleppo to come to Idlib in Syria and to Turkey.

The planned evacuation of rebel districts of Aleppo stalled on Wednesday as air strikes and heavy shelling hit the city and Iran was said to have imposed new conditions on the deal.

- Agencies.