Syrian security forces are engaged in fierce clashes with rebels on the eastern outskirts of the capital Damascus, residents say, BBC reports.
Artillery shells and rockets landed inside the heart of the city as part of a surprise rebel attack, they say.
The insurgents detonated two suicide car bombs in Jobar district before trying to storm government defence lines, observers said.
The military responded to the attack with air strikes.
Syrian state media says secret tunnels were also used to launch the assault in Jobar.