Syrian rebels on Saturday hanged two Palestinians at a refugee camp in Damascus on suspicion of aiding the regime of President Bashar Assad, a rights watchdog said.

"Rebels in the Yarmuk camp executed two men accused of cooperating with the regime by identifying targets that were bombed last week," the Syrian Observatory for Human Rights said.

"They were hanged from trees in the camp."

The Observatory, which relies on a network of activists and medics on the ground to collect information, provided a picture illustrating the hangings.

In it, two men are seen hanging from trees next to buildings as a crowd of people surrounds them, some taking pictures of the scene.

It was not possible to immediately verify the authenticity of the picture.

The Observatory says hangings of people suspected of working for the regime have been reported in Hama and Aleppo, but this was the first time that such an execution was announced along with a picture.

The Yarmuk camp housing tens of thousands of Palestinian refugees is a regular site of clashes between pro- and anti-regime supporters.