Footage emerges of 'Iranians fighting in Syria'
12 September 2013 Last updated at 14:17 BST
Video footage has emerged that appears to show Iranian nationals dressed in military clothing operating inside Syria and apparently working with government forces.
It comes as Russian and US foreign ministers prepare to hold talks in Geneva to discuss to dismantling Syria's chemical arsenal.
Mohamed Madi from the BBC's Middle East monitoring service has studied the latest footage.
The BBC has not been able to fully authenticate this footage, but based on additional checks made on it, it is believed to be genuine