Syrian rebels and regime forces have fought their most intense clashes in weeks inside the heavily guarded capital Damascus, activists say.
The sounds of shell blasts echoed through the area and residents hid in their houses and kept children home from school.
The opposition fighters blasted army checkpoints with rifles and anti-aircraft guns while government forces shelled the eastern and southern suburbs, trying to repel a new insurgent effort to push the civil war into the heart of the capital, the anti-regime activists said.
Although bordered by rebellious suburbs that have seen fierce fighting, widespread clashes have remained mostly on the capital's edges, saving it from the destruction that has ravaged other major cities such as Aleppo and Homs.
The military of President Bashar Assad has focused on securing the capital, and the dozens of rebels groups that have established footholds in Damascus suburbs have failed to form a united front, each fighting for its own area with little or no co-ordination with others.
Much of the fighting was sparked by a push by a number of rebel groups in the north-western neighbourhood of Jobar, which is bisected by the Damascus ring road. Rebels, who control the area east of the road, launched attacks on army checkpoints in the regime-controlled western part to try to seize the road, one of the capital's most important thoroughfares.
They dubbed the operation "The Battle of Armageddon". It did not appear to be co-ordinated with rebel groups elsewhere in the city.
Videos posted online showed dozens of rebels collecting in the area with rifles and rocket-propelled grenade launchers as well as rebel attacks on army checkpoints with heavy-calibre machine guns mounted on pick-up trucks. Intense gunfire was heard in the background of another video, while local mosques repeatedly broadcast "God is great" as a battle cry.
Rebels claimed to have seized at least one checkpoint near a prominent mosque on the ring road, but it was unclear where the front lines were tonight. Rebels often abandon areas soon after seizing them, fearing government shelling and air strikes.
The government responded by stopping traffic to the Abbasid roundabout on the neighbourhood's western side and closing a number of roads nearby. Activists said the army also rained shells on rebel areas east of the city. Online videos showed repeated blasts in the nearby suburb of Arbeen sending up clouds of smoke.