An agreement with Turkey on Syria’s Idlib province has not been fully implemented, raising concerns in Moscow and Damascus, Interfax news agency quoted a Kremlin spokesman as saying on Sunday.
Moscow and Ankara have tried to create a de-escalation zone in the region.
Russia said last week that the situation there was rapidly deteriorating and that it was almost under the full control of Nusra militants.
On January 11, Turkey sent a convoy of commando units and armoured vehicles to the Turkish province of Hatay on the Syrian border, state-owned Anadolu news agency said on Friday.
The convoy was being sent to reinforce a Turkish military presence on the border near the northern Syrian province of Idlib.