Turkish President Tayyip Erdogan flew to Moscow on Thursday for talks with Russia's Vladimir Putin over a potential ceasefire in Syria's Idlib, where their militaries are facing off in a war that has displaced nearly a million people in three months.
A senior Turkish official told Reuters that a ceasefire was likely to be finally agreed at the meeting, after weeks of diplomacy failed to halt fighting between Turkey and allied Syrian rebels and Russian-backed Syrian government forces.
"Political diplomacy will be more determinant today than military diplomacy," the official said.
Russian air strikes have propelled a push by Syrian President Bashar al-Assad's forces to retake the last large rebel-held territory in the northwest.
That has sparked what the United Nations says may be the worst humanitarian crisis in a nine-year war that has driven millions from their homes and killed hundreds of thousands.
Turkey, which has the second largest army in the transatlantic NATO alliance, has funneled troops and equipment into the region in recent weeks to resist the government advance and avoid a wave of refugees over its southern border.
The fighting has killed some 60 Turkish troops since early February and raised the prospect of a direct clash between Russia and Turkey, which operate on opposing sides of the front lines.
More civilians die
A Turkish security official said overnight clashes were "low in intensity for the first time in a while" ahead of the Moscow meeting, but Idlib residents reported heavy shelling by Turkish troops and air strikes by Russian and Syrian forces.
At least 16 civilians were killed when Russian air strikes hit a gathering of internally displaced people near the town of Maarat Misrin in Idlib, according to civil defense workers helping clear the rubble and search for survivors.
Turkey's state-run Anadolu news agency said the strikes hit civilians sheltering in a farm.
Two witnesses also reported seeing more Turkish military reinforcements deploying into Idlib.
The Turkish defense ministry said in the last 24 hours it destroyed four tanks, five rocket launchers and a dozen military vehicles in artillery and air strikes.
Turkey hosts some 3.6 million Syrian refugees and says it cannot handle more. To extract more funding and support from Europe over Idlib, Ankara said it would not abide by a 2016 deal in which it stopped migrants crossing into the European Union in return for billions of euros in aid.
Erdogan, who was due to meet Putin at 1100 GMT, said on Wednesday he expected his talks with Putin to reach a rapid ceasefire in northwest Syria.
Turkey wants Russia to "use its influence to ensure the attacks stop, a ceasefire is established and the Sochi agreement is re-established," another Turkish official said of the 2018 deal signed by Moscow and Ankara establishing a demilitarized zone on the edge of the Idlib region.
The official added that US counterparts on Wednesday pledged Washington's "unconditional" support for Turkish military and humanitarian activities in Idlib.
James Jeffrey, the US special representative for Syria who met Turkish officials on Wednesday, told a conference in Istanbul on Thursday that while the United States supports Turkey, it still has "very serious concerns" over Ankara's purchase of Russian S-400 missile defenses last year.