The British-based Syrian Observatory for Human Rights puts August's death toll at over 5,000, while the Local Coordination Committees, an umbrella group of local commitees monitoring violence on the ground, puts the figure at just under 5,000.

The Observatory also says more than 26,000 thousand people have been killed since the beginning of the uprising against Syria's President Bashar Assad. The figures come on a weekend of escalating violence in Damascus.

Two bombs exploded on Sunday near a government compound in the capital. Syria's state media said four people were injured in the incident, which happened in the Abu Remmaneh district. This is where security service buildings and the office of vice president Faruq al-Shara are located.

The rebel attack comes a day after a bombing near a mosque in southern Damascus killed at least 15 people.

News out of Syria cannot be independently verified, as the government imposes severe restrictions on journalists working in the country.

Brahimi speaks

Meantime, the new United Nations-Arab League envoy to Syria, Lakhdar Brahimi, said on Sunday that change in Syria was "unavoidable."

Speaking to the Arab broadcaster Al Jazeera, Brahimi refused to be drawn on the future of Bashar Assad.

"It is too early to speak about who should go and who should stay," he said.

"This is not a step backwards. Mr Assad is there and is the president of the present government," he said. "Kofi talked to him, and I will talk to him."

Brahimi took over as envoy on Saturday, replacing Kofi Annan, who blamed the failure of his six-point peace plan on a lack of support for his efforts from the international community.

Permanent UN Security Council members Russia and China vetoed three resolutions designed to put pressure on the Assad regime to end the violence.

jr/pfd (AFP, dpa)