More than 30 people have been killed in a suicide bombing and ensuing battle at a checkpoint in Damascus, activists have said.
The blast came during an attack by rebel forces near the pro-government suburb of Jaramana, the Syrian Observatory for Human Rights (SOHR) claimed.
The state news agency Sana blamed “terrorists” for the explosion and said it wounded 15 people, most of them seriously.
The pro-opposition SOHR said 15 rebels and at least 16 soldiers were killed.
Rebels control much of the countryside around Damascus but Jaramana, a Christian and Druse area, is mostly loyal to President Bashar al-Assad. Opposition fighters have previously targeted ithe suburb with bombings and mortar rounds.
Elsewhere near the capital, Syrian forces tried to storm the suburb of Mouadamiya, which the army has blockaded for months, leading to a rising death toll from hunger and malnutrition.
UK-based SOHR said the checkpoint explosion, near the suburbs of Mleiha and Jaramana, was detonated by a suicide bomber from the al-Qaeda-linked Nusra Front.
Nusra supporters on Twitter, however, said the bomber had intended to blow himself up in the car, but instead got out before setting off the explosives inside. They said rebel forces had captured the checkpoint hit by the car bomb and were battling to take a second one nearby.
Syrian state television reported the blast but gave no death toll, saying only that several people had been killed or wounded in a “terrorist bombing”.
SOHR, which has a network of activists across the country, said Syrian fighter jets retaliated by striking nearby opposition-held areas such as Mleiha.
Video uploaded by activists showed a huge column of smoke billowing up from the scene and the sound of fighter jets could be heard.
Rebels also fired rockets into Jaramana, a suburb held by the government, according to SOHR. It said the air force carried out four strikes on adjacent rebel-held districts.
More than 100,000 people have been killed in the Syrian conflict, which began with popular protests against Assad before degenerating into civil war and is now in its third year.