Syrian regime airstrikes kill dozens in and around Aleppo

At least 31 people have been killed by regime raids in and around opposition-held eastern Aleppo on Friday, the civil defence, known as the White Helmets, have said.

Ten civilians were killed when regime airstrikes hit a bus travelling on a main road near the northern Syrian city of Aleppo.

"As well as the 10 civilians killed in strikes on the bus... 21 others died in intense strikes on several neighbourhoods in the east of the city since dawn," the White Helmets said.

Eight people were killed when intense airstrikes targeted Castello road, the only route leading to rebel-held areas in divided Aleppo, the Syrian Observatory reported.

The Castello road, which is the route out of Aleppo for civilians living in the area, is now "effectively cut," Observatory director Rami Abdel Rahman said.

"All movement is targeted, be that buses or bystanders," he added.

In the past two weeks, more than 200 civilians have been killed in Aleppo after regime forces responded with air raids to rebel rocket and artillery fire.

The airstrikes on and around Aleppo mark another violation to the US-Russia-led truce agreed in February as regime forces and rebel groups continue to fight over control.

Since the war erupted in 2011, at least 280,000 people have been killed in Syria and millions displaced.