Bombing of Syrian bus convoy kills dozens outside Aleppo

A blast which hit a bus convoy waiting to enter Aleppo in Syria may have killed more than 100 people who had been evacuated the previous day.

A handout photo made available by Thiqa News Agency (TNA) showing a damaged bus at the scene of a car bomb attack that targeted buses evacuating civilians (AAP) Source: TNA/AAP

The agreement had stalled, leaving thousands of people from both government-besieged and rebel-besieged areas stranded at two transit points on the city's outskirts, before the explosion occurred.

Late on Saturday buses began crossing into both government-held and rebel-held territory from the two transit points as the deal resumed, pro-Damascus media and the Syrian Observatory for Human Rights monitoring group reported.

But the incident underscored the difficulty carrying out any agreement between warring sides in a volatile and complex Syrian conflict which, in its seventh year, shows no signs of easing.

A media unit run by Damascus ally Hezbollah said the attack was carried out by a suicide car bomb and killed at least 100 people. The Observatory said more than 24 were killed and scores more wounded.