Shells hit a building in Jobar, Damascus on Friday - as Syrian government forces battle to recapture parts of the city from rebels, according to opposition activists.

Rebel fighters broke through government lines here on Wednesday, seizing control of sections of the Damascus ring road - just 2 kilometres from security bases in the heart of the city.

Amateur videos like this one and others posted on to social media websites - which Reuters cannot independently verify - purportedly show heavy shelling and airstrikes in various parts of the capital.

This video is said to show the aftermath of an airstrike in the al-Qadam district of Damascus which rebels blame on an air strike by a Mig fighter.

Another - allegedly filmed on Saturday - shows significant damage in the town of Madyara.

President Bashar al-Assad is struggling to contain a revolt in which 60,000 people have been killed since March 2011.

While he's lost control of large parts of Syria, his forces have so far kept rebels out of central Damascus.

There were more scenes of destruction in the town of Hass in Idlib on Friday with this video purportedly showing the aftermath of another air strike.

Opposition activists said 44 people were killed in Damascus on Friday.