BEIRUT - Syrian rebels battled forces loyal to President Bashar al-Assad just outside Damascus on Thursday, forcing the closure of the main airport road, and the Dubai-based Emirates airline suspended flights to the Syrian capital.
Residents also reported Internet connections in the capital were down and mobile and land telephone lines working only sporadically in what appeared to be the worst disruption to communications in Syria since an uprising began 20 months ago.
The past two weeks have seen rebels overrunning army bases across Syria, exposing Assad's loss of control in northern and eastern regions despite the devastating air power that he has used to bombard opposition strongholds.
Rebels and activists said the fighting along the road to Damascus airport, southeast of the capital, was heavier in that area than at any other time in the conflict.
The Syrian Observatory for Human Rights, a opposition monitoring group, said clashes were particularly intense in Babbila, a suburb bordering the insurgent stronghold of Tadamon.
Nabeel al-Ameer, a spokesman for the rebel Military Council in Damascus, said that a large number of army reinforcements had arrived along the road after three days of scattered clashes ending with rebels seizing side streets to the north of it.
"There are no clashes directly around the airport; the fighting is about 3 or 4 kilometres away," he said via Skype, adding that rebels had taken control of many secondary roads and were expected to advance towards the airport.
He said that he hoped the proximity of the rebels to the airport would dissuade authorities from using it to import military equipment, but the priority now was to block the road.
A Syrian security source told Reuters on condition of anonymity that the army had started a "cleansing operation" in the capital to confront rebel advances.
Residents said the Internet in Damascus crashed in the early afternoon and mobile and land telephone lines were functioning only intermittently.
A blog post on Renesys, a U.S. company which tracks Internet traffic worldwide, said that at 12:26 p.m. in Damascus, Syria's international Internet connectivity shut down completely.
Emirates said it was suspending daily flights to Damascus "until further notice", but other airlines continued operations.
Airport sources in Cairo said an Egypt Air flight that left at 1:30 p.m. (1130 GMT) had landed in Damascus as scheduled.
"The Egypt Air plane has arrived ... and passengers are all safe but the pilot was instructed to take off back to Cairo without passengers if he felt that the situation there is not good to stay for longer," an official at Cairo airport said.
Elsewhere in Damascus, warplanes bombed Kafr Souseh and Daraya, two neighbourhoods that fringe the centre of the city where rebels have managed to hide out and ambush army units, according to opposition activists.