Turkish President Recep Tayyip Erdogan is hosting his Russian and Iranian counterparts in Ankara on September 16 for their latest meeting on Syria.
Erdogan, Vladimir Putin, and Hassan Rohani are expected to focus on the Syrian government's advance on the last rebel-held stronghold of Idlib in the country's northwest, where a cease-fire went into effect at the end of last month, following a four-month offensive by government forces.
The cease-fire has been holding despite some violations during which six people were killed last week. A major conflict in Idlib has raised the possibility of a mass refugee flow to Turkey, which already hosts 3.6 million Syrian refugees.
Last year, Russia and Turkey signed a buffer-zone agreement that is supposed to protect Idlib from a government offensive. Ankara mans 12 observation posts in the area to help enforce it, however it fears Syrian forces, who enjoy Russian air-power support, will advance on Idlib.
Hundreds of thousands of Syrians, some already displaced from other parts of the war-torn country, have moved toward Turkey's border to flee Syrian air strikes, backed by Russia.
This is the three countries' fifth summit on the Syrian civil war since November 2017.
Last month, Turkish presidential spokesman Ibrahim Kalin said the three leaders will also discuss the "establishment of a constitutional commission and how the political process should continue."
Russia and Iran support Syrian President Bashar al-Assad, while Turkey opposes him and backs certain rebel groups.
Lately, Turkey has switched more to stemming the flow of refugees from Idlib as Assad gains ground.
Erdogan has warned that Turkey could 'open its gates' and allow Syrians already living in his country to flood Western countries if Turkey is left to shoulder the refugee burden alone.
Putin, Rohani, and Erdogan last met in February.
With reporting by AFP and AP
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