Activists say at least 80 people have died after government air strikes on a marketplace in the rebel-held town of Douma, near Damascus.

Around 200 people were reportedly injured in the attack.

Government forces have been regularly attacking rebel-held Douma and its surrounding areas in recent months by air raids and helicopter barrel bomb attacks.

Hundreds of civilians have been killed alongside opposition fighters.

Images uploaded by activists said to be of the aftermath of the air strikes showed the marketplace completely destroyed, with surrounding buildings in ruins and vehicles on fire.

The Local Coordination Committees, a network of anti-government activists, said that rescue workers are digging through the rubble in search of survivors.

A Douma-based activist told AP the situation was "catastrophic", adding that clinics in the area were full and many of the wounded were being rushed in civilian cars to other medical facilities since ambulances were overwhelmed.

The latest reported strikes coincide with the first visit to the country by the UN humanitarian chief Stephen O'Brien since he took up the post in May.

Correspondents say Douma - which is only around 11km from central Damascus - has been a constant target of government air strikes aimed at stopping rebels firing rockets from there into the capital, including the Islamist rebel group Jaysh al-Islam.