Beirut - Syrian rebels battled forces loyal to President Bashar al-Assad just outside Damascus on Thursday, restricting access to its international airport, and the Dubai-based Emirates airline and EgyptAir stopped flights to the Syrian capital.

The Internet and some telephone lines went down across Syria. Rebels and the government traded blame for the blackout, the worst communications outage in 20 months of conflict.

Rebels fighting to topple President Bashar al-Assad have been making gains around Syria by over-running military bases and have been ramping up attacks on Damascus, his seat of power.

A rebel fighter who identified himself as Abu Omar, a member of the Jund Allah brigade, told Reuters that insurgents fired mortars at the airport's runways and were blocking the road linking it with the capital.

Speaking from the scene of the fighting, he said insurgents were not inside the airport but were able to block access to and from it.

A spokesperson for the rebels' Military Council in Damascus, Musaab Abu Qitada, said an artillery round was fired at a military site inside the airport and that fighting was now less than a kilometre (mile) away from the complex.

“We want to liberate the airport because of reports we see and our own information we have that shows civilian airplanes are being flown in here with weapons for the regime. It is our right to stop this,” he told Reuters on Skype from Damascus.

Two Austrian soldiers in a UN peacekeeping force deployed to monitor the frontier with the Israeli-occupied Golan Heights were wounded when their convoy came under fire near Damascus airport, Austria's defence ministry said. Syria state television said the soldiers were wounded by gunfire when rebels attacked an army position near the airport road.

The Information Ministry later said the highway to the airport was safe after security forces cleared it of “terrorists”. Rebels said fighting in the area was continuing. The ministry said the airport was operating regularly, but there were no flights scheduled to land in the evening.

The accounts of fighting could not be immediately verified because of tight restrictions on media access to Syria.

But many airlines had already halted flights. Emirates suspended daily service to Damascus “until further notice”. EgyptAir also said it was suspending all flights to Damascus because of “the deterioration of the security situation” there.

An EgyptAir flight that left at 1.30pm landed in Damascus on schedule but the pilot was instructed to take off straight back to Egypt, airport sources in Cairo said.

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 US company which tracks Internet traffic worldwide, said that at 12.26pm, the entire country's Internet connectivity shut down completely.

The government has been accused of cutting communications in previous assaults on rebel-held areas in Syria. Syria's minister of information said “terrorists” were responsible for the Internet shutdown, while the telecommunications minister blamed what he said was a fault in the main communications network.

The past two weeks have seen rebels seizing a series of 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, killing dozens of civilians as well. More than 40 000 people have been killed since the uprising began, according to opposition groups.

Rebels and activists said the fighting along the road to Damascus airport, south-east of the capital, was heavier in that area than at any other time in the conflict. - Reuters