Syrian warplanes struck rebel-held suburbs of the capital on Saturday and government forces clashed with insurgents on the frontlines, residents and opposition activists said.
"The warplanes are very busy this morning," said a journalist working in central Damascus who asked to remain anonymous for security reasons.
Activists said the strikes were focused on Berze, a north-eastern part of central Damascus, where rebels have been on the offensive to push further into the city.
President Bashar al-Assad's arsenal is vastly superior to that of the opposition and the army has stepped up operations as the threat of military action by the United States in response to an alleged chemical weapon attack last month has diminished.
The threat further subsided on Saturday after the United States and Russia agreed on a proposal to eliminate Syria's chemical weapons arsenal.
Syria's conflict began in March 2011, amidst peaceful protests against four decades of Assad family rule, but has since become a civil war that has killed more than 100,000 people.