Delegates from more than 60 countries, meanwhile, were gathering in Tokyo to find ways to step up the pressure on President Bashar al-Assad's regime.

The Syrian Observatory for Human Rights said the main road to Damascus from the airport, which was closed Thursday due to the fighting, had reopened but said a bus carrying airport employees had been hit by a shell, killing two people.

A security source also reported the deaths, blaming rebels for the shelling, but SyrianAir director Ghida Abdellatif said the two employees were wounded and that the airport itself was not shelled.

An airport source told AFP that air traffic and passenger boarding was normal on Friday, after EgyptAir and Emirates had on Thursday announced a suspension of flights because of the violence.

The airport informed foreign airlines to resume flight after "the restoration of security on the road" to the airport, he said.