Two suicide car bombers killed 55 people and wounded 372 in Damascus Thursday, state media said, in the deadliest attacks in the Syrian capital since an uprising against President Bashar Al-Assad began 14 months ago. The blasts further shredded a ceasefire which was declared by international mediator Kofi Annan on April 12, but which has failed to halt bloodshed pitting Assad's security forces against peaceful demonstrators and an array of armed insurgents. Opposition leaders said Annan's peace plan was dead, while Western powers insisted it remained the best way forward. “The government is trying to make Kofi Annan's plan fail. These bombs are not the work of opposition fighters,” said Syrian National Council chief General Mustafa Al-Sheikh, adding that the FSA lacked the capability to set off such big explosions. Annan himself condemned the “abhorrent” bombings and urged all parties to halt violence and protect civilians. “The Syrian people have already suffered too much,” he said in a statement. The near-simultaneous explosions hit the Al-Qazaz district just before 8 A.M. (0500 GMT), residents said. One punched a crater three meters (10 feet) deep in the city's southern ring road. Bloodied corpses and body parts could be seen on the road. State television also showed at least one overturned lorry. Walls of buildings on each side of the avenue had collapsed. One resident reported limited damage to the facade of the nearby Palestine Branch Military Intelligence center, one of the most feared of more than 20 Syrian secret police agencies. No group has claimed responsibility for Thursday's blasts. The attacks occurred a day after a bomb blew up near UN observers monitoring the ceasefire, which state forces and rebels have both violated, and two weeks after authorities said a suicide bomber killed at least nine people in Damascus.