Turkish President Recep Tayyip Erdogan is scheduled to travel Sept. 7 to Iran, where he is expected to take part in a three-way summit with his Iranian and Russian counterparts. Turkey’s NTV reported the meeting would likely take place in the northwestern city of Tabriz, in Iran’s East Azerbaijan province.

The three leaders last assembled in April in Ankara for deliberations on Syria, where an imminent regime assault on the rebel-held province of Idlib is occupying minds.

The United Nations has warned of a civilian bloodbath if the regime forges ahead with the kind of lethal mix of heavy aerial bombardment and attacks from the ground that allowed it to retake other areas including Ghouta and Daraa, where the Syrian uprising began seven years ago. Rebels and their families in those areas have sought refuge in Idlib, and its population is now thought to have swollen to some three million. Many would likely press against Turkey’s borders in the event of a regime strike. That is an absolute nightmare scenario for Turkey as it struggles to care for more than 3.5 million Syrian refugees on its soil amid mounting economic woes.

Turkey is begging for time to work out a deal to separate the “moderates” from the “terrorists” in the al-Qaeda-linked Hayat Tahrir al-Sham, which is the dominant force in Idlib. Erdogan will likely renew pleas for more time during his talks with Russian President Vladimir Putin and Iran's Hassan Rouhani.