Seventeen people were killed and 14 wounded when a car bomb exploded in southern Damascus on Saturday, in one of the deadliest attacks in a dozen years, state television reported.
It said a car laden with 200 kilos (440 pounds) of explosives detonated on a road leading to Sayeda Zeinab, a southern suburb of the capital.
All the victims were civilian passers-by, the television added.
It was not immediately known what the target of the attack was, but a private television station reported that the car exploded near a security checkpoint.
Journalists were prevented by security forces from approaching the scene of the blast.
A Syrian counter-terrorism unit has launched an investigation into the attack, the channel said.
The blast is the worst to rock Syria since February when top Hezbollah commander Imad Mughnieh was killed in a car bombing in Damascus.
The Lebanese Shiite militant group blamed Israel for the murder, but the Jewish state denied any involvement.
The attack also comes days after the Lebanese authorities announced on September 22 that Syria had sent reinforcements to the international border between the two neighbours.
Syria said the move was for internal security reasons.