BEIRUT, Lebanon — Rebels pushed forward in their battle with the Syrian army in Damascus yesterday, clashing with regime soldiers in contested neighborhoods in the northeast and shutting down a key highway out of the capital with a row of burning tires, sources said.

The violence has brought the civil war that has destroyed entire neighborhoods of other Syrian cities closer to the heart of the capital, which has mostly been spared heavy fighting. Still, the offensive did not appear to be coordinated with rebels on other sides of Damascus, and it was unclear whether the rebels would be able to hold their ground.