Russia's foreign ministry said on Thursday that Russian and Turkish "military specialists" were killed by militants who staged more than 1,000 attacks in the last two weeks of January in the de-escalation zone in Syria's Idlib province.
"There has recently been a dangerous increase in tension and a surge of violence in Idlib," the foreign ministry said in a statement on its website.
Russia continues to closely coordinate with Turkey and Iran on the ground in Syria, it added.
Turkey expects Russia to stop the Syrian government's attacks in the northwestern region of Idlib immediately, Foreign Minister Mevlut Cavusoglu said on Thursday, adding that Ankara needs to work with Moscow to resolve problems in the region.
Shelling by Syrian forces killed eight Turkish personnel on Monday, prompting a retaliation. The escalation disrupted a fragile cooperation between Ankara and Moscow, which back opposing sides in the conflict, raising concerns over future collaboration.
On Wednesday, Turkish President Tayyip Erdogan threatened to drive back the Syrian forces in Idlib unless they withdraw from the region by the end of month to stem an assault that he said had displaced close to 1 million people.
In televised comments to reporters in Baku, Cavusoglu said a Russian delegation would come to Turkey to discuss Idlib, adding Erdogan may hold a meeting with Russian President Vladimir Putin after those talks if necessary.
"Our expectation from the (Syrian) regime's guarantors, and specifically Russia here, is to immediately stop the regime. We are discussing these issues with Russia, with whom we have worked with until now," Cavusoglu said.
"We conveyed our determination to our Russian counterparts," he said adding Ankara was determined to stem the "humanitarian drama" in Idlib.
The violence in Idlib, the last major rebel-held stronghold in the country's nearly nine-year war, has accelerated in recent months despite several ceasefire efforts, including as recently as January, displacing hundreds of thousands of people.
The United Nations says 520,000 people have been displaced since early December and the numbers could increase.
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