A Syrian air base near the town of Rastan has reportedly been attacked on Sunday by Syrian soldiers who defected to the opposition. According to activists an entire battalion defected.

The U.S. based Human Rights Watch obtained images from DigitalGlobe that show the base burning after the reported attack, the Guardian says. The group of defected soldiers were reportedly armed with surface-to-air-missiles.

A video posted on the Guardian and uploaded on Youtube by Syrian activists reportedly shows smoke rising from the base.

The town of Rastan, north of Homs, was bombarded by the regime with armed helicopters on Monday morning in an "attempt to regain control", the Britain-based Syrian Observatory for Human Rights (SOHR) reported. Other neighbourhoods in Homs such as Jourat al-Shayyah have also been shelled.

According to the Local Coordination Committees 21 people have been killed so far on Monday.

Photo: digitalglobe 2012 analysis by Human Rights Watch via the Guardian