BEIRUT — Syrian government warplanes and artillery pounded restive suburbs of Damascus on Friday, and antiregime activists said a car bomb targeted an intelligence building north of the capital.
Fighting in Syria’s civil war has flared in areas around Damascus as rebels seeking to topple President Bashar Assad try to push into the city itself.
The rebel advances in the suburbs threaten the government’s grip on its seat of power, prompting a punishing response from the military on rebel areas skirting the capital.
Antiregime activists circulated a video they said showed an explosion near a military intelligence office in the town of Nabk, north of the capital. They had no information on casualties, and the government did not comment on the bombing.
The blast came one day after a car bomb hit a gas station in the capital, killing 11 people, activists said. While no one has claimed responsibility for the attacks, they could be guerrilla strikes by rebels groups who lack the force to battle Assad’s troops in the capital.
Syria’s 21-month conflict has turned into a bloody stalemate that the United Nations says has killed more than 60,000 people, and it warns the civil war could claim the lives of many more this year. International efforts to stop the fighting have failed so far, and although rebels have made gains in recent months, they still can’t challenge Assad’s hold on much of the country.
On Friday, the Britain-based Syrian Observatory for Human Rights said government warplanes bombed suburbs of the capital, including Douma, where twin airstrikes killed a dozen people a day earlier.
The Observatory also reported the explosion near the military intelligence building in Nabk, some 50 miles north of Damascus.
An amateur video posted online showed a large explosion and a large gray cloud of smoke billowing from the area. An off-camera narrator said the blast struck the intelligence building.
The video appeared genuine and corresponded to other Associated Press reporting.
Fighting also raged south of the capital, where rebels have been trying to push into the city for weeks.
Damascus activist Maath al-Shami said the government fired rockets and mortars from Qasioun mountain overlooking the capital at orchards near the southern suburbs of Daraya and Kfar Sousseh. The Observatory reported clashes between rebels and the army in other areas south of the capital and on the road to the city’s airport, to the southeast.
For its part, the Syrian army said in a statement late Thursday that troops had killed ‘‘terrorists’’ in areas around the capital, including Daraya.
The government says the uprising is fueled by foreign-backed terrorists who seek to destroy the country.
‘‘Regime forces are facing very strong resistance in Daraya,’’ Shami said via Skype, but he added that government forces had been able to advance down the suburb’s main road.
The government’s capture of Daraya, southwest of the city, would provide a boost to the regime’s defense of Damascus. It is close to a military air base as well as government headquarters and one of Assad’s palaces.
In the north, rebels continued to clash with government forces inside the Taftanaz air base in Idlib province and near the Mannagh military airport and the international airport in Aleppo. The attacks are part of the rebel’s effort to erode the military’s air power.
Fadi al-Yassin, an activist based in Idlib, said the rebels Thursday killed the commander of Taftanaz air base, a brigadier general.