The fighting over the past few weeks in Damascus is the most serious the capital has seen since July, when rebels captured several neighborhoods before a swift government counteroffensive swept out the opposition fighters.
Activists said forces loyal to Assad were battling rebels in towns just south of the capital, including Aqraba, Beit Saham and Yalda near the airport. The Observatory said many were feared killed in government shelling of Beit Saham.
Syrian state TV said troops were battling fighters from the al-Qaida-inspired Jabhat al-Nusra group in areas around the airport and that many of the rebels were killed, including two Iraqi citizens.
Syria’s Information Ministry said the airport was operating as usual and that the road leading to the facility is “totally secure.” The road was closed Thursday because of heavy fighting, but authorities reopened it Friday after troops secured the area, activists said.
The Observatory also reported clashes in the southern Damascus neighborhoods of Tadamon and Hajar Aswad, which have been hit by heavy fighting for weeks as the rebels try to push back into the city.
Government troops were also heavily shelling the Damascus suburb of Douma, local activist Mohammed Saeed said via Skype.
Saeed and other activists bypassed the communications blackout by using satellite telephones to connect to the Internet.
In the past, the regime has cut telephone lines and cellular networks in areas where military operations are under way, but the latest blackout was the first to cover the whole country since Syrian uprising began in March 2011.
In neighboring Lebanon, tensions were running high Saturday in the northern city of Tripoli between supporters and opponents of Assad’s regime, which is dominated by the president’s Alawite sect, an offshoot of Shiite Islam. Lebanese troops deployed to potential flashpoints in the city — home to significant Sunni and Alawite populations and the site of deadly violence in recent months between the two communities — to prevent possible clashes.
The army dispatched troops to Tripoli as a precautionary measure after an announcement Friday that 20 Lebanese Sunnis had been killed inside Syria while fighting alongside rebels, who are predominantly Sunnis as well. The city was clam Saturday.
It was not clear when the funerals would be held because the bodies of the dead are still in Syria, Lebanese security officials said on condition of anonymity in line with regulations.