Two booby-trapped cars blew up at security sites in Damascus on Friday, killing 40 civilians and soldiers and wounding about 100 more, the Syrian foreign ministry said, in the worst violence to hit Syria's capital during nine months of unrest against President Bashar al-Assad.
Al Manar, a television news channel owned by Lebanese Shia Muslim militant movement Hezbollah, a major ally of Assad, put the number of dead from the blasts at 40 with 55 wounded and said most of the casualties were civilians. Al Manar cited information from its own correspondents at the scene.
Syrian television described the attack as a suicide bombing and said initial inquiries indicated al Qaeda was behind it.
The attack came a day after the arrival of Arab League officials to prepare for a monitoring team that will check whether Assad is implementing a plan to end the bloodshed.
State television broadcast footage of bloodied bodies being carried in blankets and stretchers into ambulances and people hunting through rubble of a badly damaged building.
A Reuters cameraman was barred from the site. State television also broadcast shots of bloodied streets littered with mangled human remains and blackened debris.State television said the blasts targeted a state security administration building and a local security branch.
The United Nations says Assad's forces have killed more than 5,000 people in their crackdown on the protests, which erupted in March inspired by uprisings in Tunisia, Egypt and Libya. Syria says it faces a campaign by foreign-backed gunmen and terrorist groups. This week it said more than 2,000 members of the army and security forces had been killed since March.
Anti-Assad protests have swept the country, although central Damascus and the northern commercial city of Aleppo have remained relatively quiet.
A small blast was reported near a Syrian intelligence building in Damascus last month, but there was little damage.
But in recent months the mainly peaceful pro-democracy movement has become overshadowed by pockets of armed insurgency that have launched attacks on Syrian security forces. The escalating violence on both sides has raised fears that the country is slipping towards civil war.