Amateur video has emerged purportedly showing rocket fire directed at Damascus from a military airport on the outskirts of the city.
Syrian forces have been mounting a sustained counter-attack on rebel positions trying to stem their recent gains.
Fighting around Damascus has led foreign airlines to suspend flights and prompted the United Nations and the European Union to reduce staff, adding to a sense that the fight is closing in.
For months now, residents in the capital have seen the civil war which has claimed the lives of over 40,000 people, creep ever closer after whole swathes of Aleppo and Homs have been reduced to rubble.
Every day now, more and more Syrians are said to be quitting Damascus anxious about what the next few weeks will bring.