Syrian state television reported the blast but did not specify a death toll, saying only that several people had been killed or wounded in a "terrorist bombing".
The pro-opposition Syrian Observatory for Human Rights said Syrian fighter jets retaliated by striking nearby opposition-held areas, where clashes erupted after a suicide bomber blew himself up in a vehicle at an army checkpoint near Jaramana, a suburb of the capital.
More than 100,000 people have been killed in Syria's 2-1/2-year-old conflict, which began with popular protests against President Bashar al-Assad before degenerating into civil war.
The British-based Observatory, which has a network of activists across Syria, said the suicide bomber was from the Nusra Front, al Qaeda-linked rebel group. It said several other opposition units had joined Nusra fighters in the attack.
Activists said rebels fired rockets into Jaramana, a suburb held by the government, during the fighting. They said Assad's forces launched four air raids on rebel-held districts nearby.
