Damascus shook with loud explosions as Syrian warplanes reportedly launched their heaviest air strikes yet after a failed bid to halt the country's violence for a Muslim holiday.

The blasts on Monday, heard coming from several districts, were among the most intense in the capital since the beginning of Syria's 19-month conflict.

They were followed by a car bombing that state television said killed at least 10 people in the predominantly Christian and Druze area of Jaramana, just outside Damascus.

The fresh violence came as world powers looked to pick up the pieces of the failed ceasefire effort, with UN-Arab League envoy Lakhdar Brahimi in Moscow and due in China later this week, as he prepares to present new ideas to the UN Security Council.