A car bomb in central Damascus has killed 53 people and wounded around 200, Syrian television said.
The device exploded near a busy motorway in the capital, close to the ruling Baath Party offices.
Syrian state media said this was an attack by “terrorists” battling President Bashar al-Assad.
Most of the victims in the Mazraa district had been civilians, possibly including children from a nearby school.
The British-based Syrian observatory for human rights said the car-bomb, which struck just before 11am local time, also blew out the windows of the Russian embassy 200 metres away.
Two other car bombs were reported outside security centres in the northeastern district of Barzeh, but there were no details of casualties.
The opposition Syrian national coalition has said it is open to talks with the regime to end the 2-year conflict, that has cost around 17,000 lives, but they said al-Assad cannot be party to any settlement and called for the release of tens of thousands of detainees which the government refused.
This comes as British foreign secretary William Hague, who is in Lebanon to discuss the Syria crisis, reiterated his calls for al-Assad to step down:
“Such a threat to the stability of the whole region should not be endured because one person wishes to stay in power,” he said.