A blast was heard near a bus convoy evacuating residents of the besieged Shiite towns of Fua and Kefraya to Aleppo, local TV reported. Over 20 civilians are reportedly dead.
The explosion hit the Rashidin area on Aleppo's outskirts. The bus was waiting for entering the city of Aleppo.
According to Al-Ikhbariyah television channel, the explosion left 22 people killed and some 50 injured.
According to a Sputnik source in Aleppo, the blast supposedly was caused by a suicide attacker who detonated an explosive device.