Russia has charged that U.S. reluctance to do more to combat Syria's Al-Qaeda affiliate remains an obstacle to reaching agreement to cooperate in Syria.
The Russian Foreign Ministry warned on August 23 that the U.S. failure to move against the Al-Nusra Front, recently renamed Jabhat Fateh al-Sham, risks creating a "new terrorist monster in Syria."
Russia's accusations came one day after U.S. Secretary of State John Kerry said U.S.- Russian talks on finding avenues to cooperate in Syria are nearing an end.
Al-Sham has been one of the most effective rebel groups fighting the Russia-backed Syrian regime, and it has ties to other rebel groups supported by the United States.
"Washington agrees that Al-Nusra Front...is a terrorist organization. But it has not been the target of strikes" carried out by the U.S.-led coalition fighting the Islamic State in Syria, the Russian ministry said.
"It has been nearly a year in which the Americans have refused to share with us their data on the location of Al-Nusra militants," it said.
"Instead of taking practical steps, the Americans have made any intensification in their fight [against Al-Nusra] conditional on promises of [regime] change," it said.