Moscow says Washington must do more to ensure the cessation of hostilities continues in Syria.
Russia's Defense Ministry said in a statement on March 19 that "on the whole the cease-fire regime between government troops and opposition forces on the territory of Syria is being observed."
But it claimed that opposition fighters in the Homs region had opened fire on government posts, killing one soldier.
The statement criticized the United States for what it said was Washington's failure to restrain rebel fighters.
There was no immediate reply from Washington.
The cease-fire that took effect in Syria three weeks ago has reduced violence but not fully halted fighting as peace talks take place in Geneva.
The cessation of hostilities accord, agreed by the United States, Russia, and other powers in Munich on February 11, does not include Al-Qaeda or Islamic State militants.
Based on reporting by Reuters