The Fate of Syria's Idlib to Top Turkey, Russia, Iran Talks video player.

ISTANBUL - The Turkish, Iranian and Russian presidents will meet in Ankara Monday to discuss Syria and the last rebel enclave in Idlib. Syrian regime forces are threatening to overrun Idlib, and Ankara is warning of a humanitarian disaster.

The three-way summit is being held under the auspices of the Astana Process, set up to resolve the Syrian civil war.

In the past few weeks, Syrian regime forces have pounding rebels in Idlib. Many of the enclave’s estimated 3 million inhabitants are fleeing toward the nearby Turkish border.

Avoiding a humanitarian crisis is predicted to be Turkish President Recep Tayyip Erdogan’s priority when he hosts Iranian President Hassan Rouhani and Russian President Vladimir Putin.

International relations professor Mesut Casin of Istanbul’s Yeditepe University warns Turkish-Russian rapprochement could be at risk over the situation in Idlib. (D. Jones/VOA)

“The situation is very critical,” said Mesut Casin about Idlib. The Yeditepe University professor said, “In the area, half million people are reported around 10 kilometers from the Turkish border. This is an ongoing situation, an unacceptable situation.”

Many Syrian refugees in Idlib have set up in makeshift camps close to the Turkish border. The area was hit this week with the first autumn storms causing flooding.

Turkey already hosts almost 4 million Syrians, with Erdogan warning his country can take no more.

With mounting public discontent over the presence of the Syrians, Turkish authorities have started to round up undocumented refugees in many of Turkey’s largest cities. It is also strengthening sections of a recently constructed border wall along with the Idlib province.

Many Syrian refugees have sought refuge in Turkey's main cities, including Istanbul, where public discontent is growing. (D. Jones/VOA)

Erdogan is expected to look for support from Putin at Monday’s summit to avert a new refugee exodus from Idlib, which some experts estimate could be as many as a million people seeking sanctuary.

“Many of the people in Idlib have fled Assad and will not be prepared to reconcile with him or his regime,” said former senior Turkish diplomat Aydin Selcen, who served across the region. “So they will have only one option — to go to Turkey.”

Despite backing rival sides in the Syrian conflict, the Russian and Turkish leaders have been cooperating on Syria, as part of a broader rapprochement. Earlier this month Erdogan visited Putin in Moscow to discuss Idlib.

However, some predict Erdogan is set to be disappointed by Putin at Monday’s summit.

Former senior Turkish diplomat Aydin Selcen warns President Recep Tayyip Erdoğan is likely to be disappointed at Ankara summit. (D. Jones/VOA)

“The Astana Summit in Ankara will only delay what is to come in Idlib,” said Selcen, “which is Idlib will be part of the Syrian State and Bashar Assad.”

“The Syrian Army doesn’t have the muscle to push the Turkish Army out of Syria,” he adds “But Russia also supports Syria. And the endgame is near. All parties, including Russia and the United States, now wish to move on to the next step, which is the writing of the new (Syrian) constitution.”

Last year Putin and Erdogan reached an agreement that averted a Syrian regime offensive against Idlib. However, Moscow and Ankara remain at loggerheads over which rebel groups in Idlib should be designated terrorists. Russian officials are accusing Turkish forces in Idlib of failing to disarm radical groups and preventing rebel groups from attacking Russia’s bases in Syria.

Patience is running out in Moscow and Damascus, warns analyst Atilla Yesilada of Global Source Partners.

“There is little hope the Astana Summit will result in a deal that would allow Erdogan to keep Idlib City, and the northern part of the province to launch (Syrian) resettlements,” he said.

But he added, “It’s a mistake to think Turkey is defeated in Idlib and shall quietly withdraw,” said Yesilada, “Erdogan will be left with one choice: risk a break-up with Russia to defend Idlib city at any cost.”

Turkey is reinforcing its military presence and beefing up its fortifications across Idlib and bringing with it the threat of a clash between Turkish and Syrian forces.