Syrian rebels claimed on Monday to have seized an undisclosed number of missiles from the army's arsenal in the east of Damascus province.

"With the help and grace of God we overcame an air defence unit specialising in missiles," said a rebel commander, in a video posted on YouTube and publicised by the Syrian Observatory for Human Rights.

"Of course the rebels can do nothing with these missiles," Observatory director Rami Abdel Rahman said.

"But their capture is significant, partly because of the size of the operation but also because of its location in the Eastern Ghuta area of Damascus province," Abdel Rahman told AFP.

The Eastern Ghuta area is home to some of the best-organised rebel Free Syrian Army groups. A number of high-profile operations in Syria's 18-month conflict have been claimed by battalions based in the area.