At least 109 people have been documented as killed and up to 400 more are likely to have died in an almost week-long offensive by forces loyal to Syrian President Bashar al-Assad on a rebellious Damascus suburb, opposition activists said, according to Reuters.

If the accounts are confirmed, the killings in the mainly Sunni Muslim suburb of Jdeidet al-Fadel would amount to one of bloodiest episodes of the two-year-old uprising against Assad. Many of the dead were civilians, the activists said.

Syrian state media gave no death toll but confirmed the army had been fighting in Jdeidet al-Fadel. It said it had saved the town from what it described as criminal terrorist groups, killing and wounding an undisclosed number of them.

On Sunday activists said at least 85 people had been killed and the toll might reach 250, but with the army beginning to pull back they said more accounts were emerging which suggest the final figure could be even higher.

The activists, speaking from the area, 10 km (six miles) southwest of Damascus, said residents had buried some victims in the early stages of the five-day attack by elite forces and pro-Assad militias. More bodies are now being found burnt or summarily executed in buildings and streets.

They said rebel brigades who numbered around 300 fighters withdrew two days ago, leaving Assad's forces in total control.