ISTANBUL－As global and regional powers are wrestling over how best to deal with rebels in their last major stronghold in the Syrian province of Idlib, Turkish analysts warn that the planned offensive risks further deepening divergences between Turkey and Russia.

"The Teheran summit has already amply revealed the differences between Ankara and Moscow over Idlib," said Haldun Solmazturk, a former army general.

Turkish President Recep Tayyip Erdogan's call for a cease-fire in the province was not accepted by Russia or Iran at the tripartite summit in Teheran on Sept 7.

Days before the meeting, Syrian and Russian forces began pounding rebel positions in Idlib in northwestern Syria, drawing criticism from Ankara.

Ankara, Moscow and Teheran are partners in the Astana process aimed at ending clashes and setting the stage for a political settlement in Syria.

Erdogan and Russian President Vladimir Putin were scheduled to meet again on Monday in Russia's Sochi, which indicates that tension is building over Idlib and things are getting serious, said Solmazturk, who chairs Incek debates at the Ankara-based 21st Century Turkey Institute.

"The failure of the Teheran summit to address the very issue probably marks the end of the Astana process," said Faruk Logoglu, a former diplomat.

The Syrian army is preparing to launch an all-out offensive to wipe out the rebels from their last major stronghold in Idlib.

Remarks made by top Turkish officials in the wake of the Teheran summit suggested that Ankara would not remain silent should the Syrian army launch a full-scale assault.

Erdogan said it was vitally important to maintain Idlib's current status as a de-escalation zone. A Syrian offensive would collapse the ongoing Astana process.

In Solmazturk's view, Erdogan will try to talk Putin out of launching an offensive against the Idlib rebels at the Sochi summit. "It's more probable that Putin would persuade Erdogan," he said, arguing that Putin would not have flatly rejected Erdogan's proposal for a cease-fire if Moscow were not determined to eliminate the terrorism threat in Idlib.

Moscow and Teheran have been supporters of Damascus in the war, while Ankara backed, together with the United States, the rebels in efforts to topple the Syrian government.

"Ankara must understand that Idlib is a Syrian territory and the best path to follow is to help restore Syrian sovereignty there without harm to civilians and without a bloodbath," said Logoglu. "This requires getting in touch with the Syrian government."

Xinhua