Lebanese resistance movement Hezbollah has forces fighting alongside pro-government forces in Syria. The Sunday Times in London reported in June there were 300 U.S. Marines deployed in Jordan to help with the transfer of military assistance to anti-government forces.
Russian Deputy Foreign Minister Mikhail Bogdanov told state news agency RIA Novosti bilateral exchanges with the Syrian government concerned a wide range of foreign fighters.
"There are hundreds of mercenaries, militants from different states, including from European countries and the United States," he said Friday. "Russians are formally there too, but [they] are fighting for the rebels of illegal militant groups linked to an underground terrorist resistance movement, and are affiliated with al-Qaida."
The Kremlin in June said there may be as many as 600 militants from Russia and Europe fighting pro-governments forces in Syria.
Russian opposition to draft resolutions at the U.N. Security Council has thwarted international efforts to find a way to resolve the Syrian situation, which began in early 2011. Russia is one of Syria's main weapons suppliers, though Moscow said it is obligated to fulfill contracts made before conflict began.