Two large explosions hit Damascus on Saturday, killing several security force personnel and civilians, state television reported, blaming what it said were terrorists behind the year-long uprising against President Bashar Al-Assad.

Video from a blast at an intelligence centre showed the front of the building blown away, with numerous burnt out cars littering the street below.

The second bomb targeted a police building, with television showing the smouldering wreckage of a car at the site, and what appeared to be at a charred corpse inside the mangled shell.

A minivan nearby had a pool of blood on the floor. Its doors and windows were shattered and its panels were also stained red with blood. Damascus residents said clouds of black smoke could be seen rising from the areas where the blasts struck.

No one claimed responsibility for the twin attacks, which appeared to be similar to suicide bombings that struck Damascus and Syria's second city Aleppo in the last three months.

The explosions came two days after the first anniversary of year-long uprising, in which the United Nations says more than 8,000 people have been killed and some 230,000 forced to flee their homes as the violence spreads.

The U.N.-Arab League envoy for Syria, Kofi Annan, warned on Friday that the crisis could spill over into other neighbouring countries and urged international powers to lay aside their differences and back his peace initiative.

While the West and much of the Arab world have lined up to demand that Assad steps down, his allies Russia, China and Iran have defended him and cautioned against outside interference.

"The stronger and more unified your message, the better chance we have of shifting the dynamics of the conflict," an envoy said, summarizing Annan's remarks to a closed-door meeting of the 15-nation Security Council.

Turkey said on Friday it might set up a "buffer zone" inside Syria to protect refugees fleeing Assad's forces, raising the prospect of foreign intervention in the revolt, although Ankara made clear it would not move without international backing. – Reuters