Huge car bomb hits Damascus, more than 50 feared dead (VIDEO)

At least 53 people are reported dead and more than 200 injured after a car bomb exploded in Damascus, the latest and most deadly in a string of attacks on the Syrian capital.

Witnesses described seeing a vehicle blown up at a security checkpoint between the headquarters of Syria's ruling Baath party and the Russian Embassy in the central neighborhood of Mazraa, the Associated Press said.

Residents said the blast was "huge." Pictures showed a crater in the road, cars burning and smoke billowing over the city. Several charred bodies lay on the ground.

The majority of the victims were civilians, according to the UK-based Syrian Observatory for Human Rights, though some members of the security forces were also reported killed.

State news agency SANA said that 235 people were taken to hospital with injuries. Some of the casualties were children who attended a nearby school, it reported.

SANA blamed the attack on "terrorists." Its report claimed that police had arrested a would-be suicide bomber in a car packed with explosives, though it wasn't clear how that was connected to the blast.

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Shortly afterward, activists said two more car bombs had exploded near security posts in the northeast Barzeh neighborhood of Damascus. Two mortar shells were also reportedly fired at a military headquarters in a heavily fortified area of the capital.

The attacks follow two days of shelling in Damascus, first near one of President Bashar al-Assad's palaces and then at a sports stadium.

Amid the escalating violence, the "official" Syrian opposition, the Syrian National Coalition, is meeting in Egypt today to draw up its terms for a possible peace deal.

According to a draft comminqué seen by Reuters, the group maintains that Assad and his regime must be held accountable for their "crimes," but does not insist that the president must be gone before it will consider talks. Reuters called that position "a softening of tone."

Russia and the Arab League, meanwhile, have said that they want to broker direct negotiations between the opposition and the government.

Anything other than a negotiated peace is "a road to nowhere, a road to mutual destruction of the people," the BBC quoted Russian Foreign Minister Sergei Lavrov as saying.