Syria's state television says a powerful explosion has hit central Damascus.
It said 13 people were killed and 70 were injured, while the London-based Syrian Observatory for Human Rights said the blast in the capital's Marjeh district killed nine civilians and three security personnel.
The observatory said the death toll was likely to rise.
Video broadcast on state television showed smoke billowing over the site of the explosion and bodies lying in the street.
The blast came a day after an attack in Damascus targeted Prime Minister Wael al-Halki.
The prime minister escaped unharmed, but one of his bodyguards and five other people were killed.
Damascus has seen a number of major bomb attacks in recent weeks.
On April 9, a massive blast in the capital's center killed at least 15 people.
Based on reporting by Reuters and AFP