The situation in Syria's Idlib province where Russia and Turkey have tried to create a de-escalation zone is rapidly deteriorating, Maria Zakharova, a Russian Foreign Ministry spokeswoman, said on Wednesday.
The territory is now almost under full control of Nusra militants, she said.
"Continuing provocations pose a threat to civilians, Syrian military personnel and the Russian Khmeymim air base," Interfax citing Zakharova as saying.