ISTANBUL - A Russian-backed Syrian government offensive against the rebel-controlled Idlib enclave is putting Turkey's recent rapprochement with Russia to the test. Ankara, which backs the rebels, is voicing alarm over the attack, warning of a "humanitarian crisis."
With Damascus stepping up its assault on Idlib, Turkish President Recep Tayyip Erdogan reached out Friday to his Russian counterpart, President Vladimir Putin.
"Erdogan told Putin that attacks and cease-fire violations in Idlib have resulted in a major humanitarian crisis and have become a very serious threat against Turkish national security," the official Turkish readout of the telephone conversation said.
Moscow said "they agreed to activate mutual efforts, with the goal of liquidating the terrorist threat coming from this region."
While Moscow and Ankara back rival sides in the Syrian civil war, the two countries have been cooperating to end the conflict, as part of a broader rapprochement.
"Idlib is one of the main stress tests of the relationship if the situation really gets out of hand," said Galip Dalay, a visiting scholar in international relations at Oxford University.
Last September, Ankara and Moscow brokered a deal to prevent a Syrian government offensive against rebels in Idlib. Along with a cease-fire, the agreement created a buffer zone between rebels and the regime forces. Ankara also committed to disarm rebels linked to terror groups.
Twelve Turkish military observation posts were set up across Idlib as part of monitoring efforts.
Turkish media reports say Syrian government helicopters opened fire close to one of those outposts. Another report said an observation post is now surrounded by Syrian government forces.
Monday, a Turkish convoy supplying one of the outposts was hit by an airstrike, killing several civilians, but there are no reports of any military casualties. Turkey's intelligence chief, Hakan Fidan, was reportedly dispatched to Moscow after the Syrian airstrike.
Moscow is defending the Syrian government offensive, with Russian jets supporting the ongoing assault. Russian Foreign Minister Sergey Lavrov accused Ankara of failing to disarm terror groups in Idlib.
"We have made it clear that if [terrorist groups] carry out attacks in this area, they will be severely suppressed. These provocations have not stopped over the course of this year," Lavrov said Tuesday at a press conference.
Turkish President Erdogan has so far avoided publicly criticizing Moscow. Next month, Putin, Erdogan, and Iranian President Hassan Rouhani are scheduled to hold a summit in Turkey on the Syrian conflict. The three leaders have regularly met under the "Astana Process," which aims to end the civil war.
Some experts warn even before next month's summit, the conflict in Idlib risks a direct confrontation between Turkish and Syrian government forces. Ankara is sending arms to the rebels in Idlib, while Turkish troops are massed on the Syrian border.
"I think it is increasingly becoming a reality [a conflict between Syrian and Turkish forces]. I would not have said this, a couple of weeks ago," said International relations Professor Huseyin Bagci of Middle East Technical University.
"Because the Russians are unconditionally supporting Syrian forces," he added, "and Syrians feel that Idlib must be saved and put under Syrian control and they have now a free ride. They are strong; they have air power superiority; once again. Turkey is not wanted in Syria."
However, Ankara fears, if Idlib falls to Syrian forces, it will trigger a significant exodus of refugees into Turkey. Around three million Syrians are believed to be in the rebel enclave, of which half are reported to be refugees from other parts of Syria.
Local media reports claim 200,000 Syrians have fled to the northern part of the province, which borders Turkey, to escape current fighting.
The Turkish Red Crescent said Friday preparations to receive 150,000 refugees had been made. Tens of thousands of Syrians are reportedly camped close to the Turkish border.
Ankara is already struggling to deal with over 3.5 million Syrian refugees, with mounting public discontent. A recent opinion poll found over 80% of Turks want the Syrians to leave.
Analysts warn another exodus would pose both a humanitarian and political crisis for Ankara, as well as dealing a significant blow to Turkish-Russian relations.
"If we see hundreds of thousands of refugees heading to Turkey then I don't think the current mode in Turkish-Russian relationship can continue. I think it will have a major impact on the relationship," said Dalay, who is also a research director of the Istanbul-based Middle East research group al-Sharq Forum.
Bagci warns the escalating crisis in Idlib is giving Ankara a painful lesson on the limitations of the Turkish Russian rapprochement.
"Russia is not so interested in Turkey's interests," said Bagci. "Russia is only interested in their interests in the Middle East, which means military bases, good relations with Egypt, Saudi Arabia, Israel and Syria. Putin will tell Turkey how far it can go and how far it can't go."