Syrian regime forces on Thursday took control of Idlib province's Khan Shaykhun town from opposition fighters.
The Bashar al-Assad regime took control of the town with support of Iranian-backed foreign terrorist groups and Russian special forces.
Turkey and Russia agreed last September in Sochi to turn Idlib in Syria's northwestern into a de-escalation zone where acts of aggression are expressly prohibited.
Under the deal, opposition groups in Idlib would remain in areas where they were already present, while Russia and Turkey would carry out joint patrols in the area to prevent a resumption of fighting.
The Syrian regime and its allies, however, have consistently broken the terms of the cease-fire, launching frequent attacks inside the de-escalation zone.
The de-escalation zone is currently home to some 4 million civilians, including hundreds of thousands recently displaced by regime forces throughout the war-weary country.
- 'RUSSIA IN COOPERATION WITH TURKEY'
Russian Foreign Ministry spokeswoman Maria Zakharova said on Thursday that Moscow will continue its cooperation with Turkey within the framework of Sochi deal.
"Regarding the situation in Idlib, we believe it is important to adhere to all the agreements on Idlib, aiming both to continue the fight against terrorists and to ensure the security of the civilian population," she said.
Zakharova also expressed Moscow's commitment to the implementation of the relevant agreements with Ankara.
"...not everything is going as planned, but at the same time we are in contact with our Turkish colleagues to fine-tune the agreements that we have reached," she added.
Syria has been locked in a vicious civil war since early 2011, when the Assad regime cracked down on pro-democracy protests with unexpected ferocity.
Since then, hundreds of thousands of people have been killed and more than 10 million others displaced, according to UN officials.