DAMASCUS - A video appeared on-line Thursday showing the Western-backed armed rebels executing as many as 20 Syrian soldiers in the northern province Idlib.

Syrian refugees are seen in a refugee camp on the Syrian side of the border with Turkey, near Idlib October 31, 2012. Picture taken October 31, 2012. [Photo/Agencies]

In the video, the rebels had the soldiers lying on ground and stepped over them before showering them with gunfire.

The Britain-based Syrian Observatory for Human Rights said the mass killing of the government soldiers occurred after the rebels have taken over a checkpoint in an area west to the town of Saraqeb in Idlib.

Idlib has emerged as a stage for intense fighting between the armed rebels and the Syrian troops.

Meanwhile, the Observatory placed the death toll of Thursday's violence at 157, including 50 civilians and 72 regular forces.

Still, neither the activists' video nor their account could be checked independently.