The Free Syrian Army opposition group has denied that it receives military support from Russia to fight DAESH, despite contrary comments from the Kremlin.
On Monday, Kremlin spokesman Dmitry Peskov said Russia is helping the rebel group with air strikes.
Peskov said, "It is true that some forces of the Free Syrian Army are involved in offensive operations against the ‘Islamic State’ [DAESH] and other extremist groups. These offensive operations have support from the Russian armed forces."
Russian Chief of General Staff Valery Gerasimov, meanwhile cited, "The number of such FSA units is on the rise. The Russian aviation carries out 30-40 airstrikes daily to support them."
"We also supply them with weapons, ammunitions and materials," he said, adding the FSA is fighting against DAESH along with regulars of the Syrian army in Homs, Hama, Aleppo and Raqqa provinces.
The FSA has about 5,000 troops and is formed of previous members of the Syrian army who have deserted since the start of the country's civil war in 2011.
Gerasimov explained the offensive against DAESH as a coordinated effort by FSA and the Syria's regime military although FSA has been in opposition to the leader of the regime in Syria, Bashar al-Assad.
FSA spokesman Issam al-Reis said the group would not join "assisting a regime that indiscriminately kills their own people."
The rebel group previously refused military help from Russia due to its support of Assad, and said on Saturday that the Kremlin allegations of support were not true.
FSA Chief of Staff Brig. Gen. Ahmed Berri referred to Russia as an aggressor country.
He said Russian air strikes on FSA and civilian positions occur almost everyday.
US State Department spokesman John Kirby commented on the reports of Russian cooperation with the FSA, "It's unclear to us ... if these claims of support to the FSA are true or false."
Russia has not given the names of the FSA groups, many of which identify themselves as part of the FSA that does not have a central command and control structure.
When Russia first started air strikes in October in Syria, a US-led coalition targeting DAESH in the country accused Russia of bombing areas held by rebel groups in an effort to back Assad.
"These military actions constitute a further escalation and will only fuel more extremism and radicalization," a statement from the coalition in October said.
British Defense Minister Michael Fallon, speaking in Washington in a joint press conference with US Defense Secretary Ashton Carter On Friday, called for additional assistance from Russia to defeat DAESH and for them to stop supporting the Assad regime.
"They began by bombing the Free Syrian Army. If they're now ... claiming to be supporting the Free Syrian Army, I mean, that is welcome," Fallon said.
"What they've got to do is stop propping up the Assad regime; stop bombing opposition groups who are opposed to the Assad regime; stop dropping unguided munitions on innocent villages and groups who've been fighting Assad; and get behind the political process that is now underway of leading that country to a more -- a more pluralist government and a future without Assad."
Some of the most powerful FSA groups have been regularly targeted in the Russian aerial campaign that has received military support from Saudi Arabia and the United States.