Two bombs exploded outside the Palace of Justice in central Damascus, state television reported, without giving any immediate word on any casualties.
"Two bombs exploded in the car park of the Palace of Justice in the Al-Marjeh district of Damascus. A third did not explode," the television said on Thursday, describing the bombings as "terrorist" attacks.
A police source told AFP news agency that two magnetic bombs exploded in two judges' cars in the open-air car park, while a third was in the process of being defused.
State television showed footage of heavy smoke rising from the car park, as firefighters attempted to put out the flames.
Al Jazeera's Rula Amin reports on the blast from Beirut in neighbouring Lebanon
A reporter with Associated Press news agency at the scene said some cars were charred and many had their windshields blown out.
Fawaz Mishhim, a witness who was in a nearby market when he heard the explosion, said: "I did not see any wounded people, but cars and nearby shops were damaged."
The blast happened at around 1pm local time (10GMT) near al-Hamidiyeh Market, a busy commerical area in the heart of Damascus.
Syria has been hit by a wave of massive explosions in recent months, killing dozens of people. Most of the explosions targeted the security agencies of President Bashar Assad, who is fighting to end a 15-month-old uprising against his rule.
Last month, an explosion targeted a military intelligence compound south of Damascus killing 55 people. It was Syria's deadliest blast.
Much of the violence that has gripped Syria since the uprising began has been sanctioned by the government to crush dissent.
Rebel fighters are launching increasingly deadly attacks on government targets.
On Wednesday, at least seven people have killed been killed after gunmen raided the offices of a pro-government television station near Damascus.
Source: Al Jazeera and agencies