Putin Assad Moscow meeting
Russian President Vladimir Putin shakes hands with Syrian President Bashar al-Assad during a meeting at the Kremlin in MoscowReuters

The Syrian rebel group Free Syrian Army (FSA) has turned down Russia's offer to play a mediatory role in the strife-torn country. Russia earlier expressed readiness to help the Western- and Gulf nations-backed rebel forces in their fight against Islamic State (Isis).

FSA, the key anti-Assad umbrella group, ruled out any sort of cooperation with Russian forces until Moscow stops bombarding targets in Syria and its support to the Syrian regime.

"Russia is bombing the Free Syrian Army and now it wants to cooperate with us, while it remains committed to Assad? We don't understand Russia at all," said Lieutenant Colonel Ahmad Saoud, a spokesperson for the FSA, according to the AFP news agency.

Russia's Foreign Minister Sergei Lavrov earlier said Moscow's air force would provide cover for the rebel group if the US intelligence shared their positions with Russia. The US has been accusing Russian forces of targeting the positions of rebels including those of the FSA.

In a sharp switch from Russia's original position of staunch support for the Syrian regime, Lavrov said: "The Americans' refusal to coordinate their anti-terrorist campaign with us is a big mistake. We are seriously prepared for such coordination.

"We are ready to give air support to the patriotic opposition, including the so-called Free Syrian Army, but we need to get in contact with the people who will have the authority to represent certain armed groups."

Responding to the offer, other anti-Assad groups have also accused Moscow of being hypocritical. Samir Nashar, a member of the Syrian National Coalition, the political wing of the rebel forces, said: "Instead of talking about their willingness to support the Free Syrian Army, they should stop bombing it."