Rebels and allied jihadists, led by former Al-Qaeda affiliate Fateh al-Sham Front, launched an attack early Sunday on government positions in east Damascus, initially scoring gains.
But forces loyal to President Bashar al-Assad drove them back by nightfall and began a fierce bombing campaign yesterday morning, a monitor said.
"There have been intense air strikes since dawn on opposition-held positions in Jobar from which the offensive was launched," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.
"The government and allied forces have retaken the initiative and are striking the groups that launched yesterday's assault," he added.
Control of the district - a battleground for over two years and is the closest rebel position to the heart of Damascus - is divided between rebels and allied jihadists on one side, and government forces on the other.