The evacuation of more than 3,000 Syrians from four areas as part of a population transfer has been postponed a day after a deadly blast killed more than 120 people, many of them government supporters.

LATEST: At least 100 people have been killed in the blast near evacuation buses outside Aleppo city, the Syrian opposition rescue service says.

Convoys are delivering aid for the second time this week to three besieged communities in Syria in an effort to alleviate civilian suffering in cut-off areas.