The leaders of Russia, Iran and Turkey are meeting in Ankara to discuss the Syrian conflict.
Topping the agenda of Monday's meeting is the volatile situation in northwestern Idlib province - the last rebel stronghold in Syria.
A cease-fire that went into effect there at the end of August, following a wide four-month offensive by government forces, has been holding despite some violations that left six people dead last week.
The conflict in Idlib has raised the possibility of a mass refugee flow toward Turkey's border. Turkey already hosts 3.6 million Syrian refugees.
The meeting is the fifth such trilateral meeting of countries who stand on opposing sides of the conflict.
Russia and Iran are key allies of Syrian President Bashar Assad while Turkey backs Syrian rebels seeking his ouster.