Fighting forced the closure of the road between Damascus and its international airport on Thursday, a watchdog said, with Emirates saying it had cancelled its flights to the Syrian capital.
"The road to Damascus international airport was closed because of ongoing fighting and military operations in the surrounding areas," the Syrian Observatory for Human Rights said.
Employees at the airport confirmed that the road was closed and were unable to say when it would be open again, local residents told AFP.
In Dubai, Emirates said it suspended flights to Damascus after Syrian authorities had reportedly blocked the airport road due to clashes in nearby suburbs.
"Emirates has suspended all flights to and from Damascus effective immediately and until further notice," a spokesperson for the company said.
"Emirates apologises for any inconvenience caused to its customers. However, the safety of our passengers and crew is of the highest priority and will not be compromised," the spokesperson said.
The road to the airport, located 27 kilometres (17 miles) from the centre of Damascus, passes through the embattled Eastern Ghouta region.
Regime forces have regularly carried out air strikes on this area, in an attempt to dislodge rebels from their rear bases in the orchards on the outskirts of the capital.
The goal of the army is to take full control of the capital and a radius of eight kilometers (five miles) around it, a Syrian security official told AFP.