Syrian activists say a car bombing has killed at least 31 people near the headquarters of the country's ruling Ba'ath Party in central Damascus.
The Britain-based Syrian Observatory for Human Rights said Thursday most of the dead were civilians.
Syrian state media called the blast a "terrorist bombing" that struck a densely populated area near the al-Mazraa neighborhood.
The explosion comes a day after Syrian activists said rebels shot down a warplane outside Damascus, shortly after an airstrike killed at least 20 people in the same area.
Amateur video circulated by the Britain-based London Observatory for Human Rights showed a warplane firing rockets and then plummeting to the ground in Hamouriya after apparently being hit by rebel machine gun fire. The shoot-down could not be independently verified.
Earlier Wednesday, SANA said two mortar shells struck near a stadium complex in Damascus, killing a soccer player.
The shells exploded outside a hotel housing soccer players next to the Tishrin stadium. There was no immediate claim of responsibility.
Rebel sources claimed to have targeted pro-government Ba'ath Party offices in the capital, but say the mortar fire missed the intended target.