Ankara. The recent rapid advance by opposition fighters in Syria shows that Syrian President Bashar Assad must reconcile with his own people and hold dialogue with the opposition, the Turkish foreign minister said Monday.

At a joint news conference in Ankara with his Iranian counterpart, Hakan Fidan said Turkey and Iran, which support opposing sides in Syria’s civil war, have agreed to resume diplomatic efforts along with Russia to restore calm days after insurgents launched a lightning offensive and captured almost all of the country’s largest city, Aleppo.

The swift advance by fighters that Turkey supports was a huge embarrassment for Assad and it comes at a time when his allies — Iran and groups it backs and Russia — are preoccupied with their own conflicts.

The push is among the rebels’ strongest in years and raises the prospect of another violent front reopening in the Middle East when US-backed Israel is fighting Hamas in Gaza and Hezbollah in Lebanon, both Iranian-allied groups.

Fidan, whose country has backed forces opposed to Assad, blamed the recent flare-up of the conflict on the Syrian government’s refusal to enter a dialogue with the opposition that Turkey supports.

“Recent developments show once again that Damascus must reconcile with its own people and the legitimate opposition,” the Turkish minister said. “Turkey is ready to make all the necessary contribution toward this.”

Fidan’s comments emerged amid Turkish frustration that recent efforts toward reconciliation with Assad have fallen flat. The comments indicated that the shock offensive launched by opposition fighters could be aimed at pressuring the Syrian leader to engage in political talks.

Turkey has been seeking to normalize ties with Syria to address security threats from groups affiliated with Kurdish militants along its southern border and to help ensure the safe return of more than 3 million Syrian refugees. Assad has insisted that Turkey’s withdrawal of its forces from northern Syria be a condition for any normalization between the two countries.

Iranian Foreign Minister Abbas Araghchi, who visited Assad on Sunday before traveling to Ankara, reiterated Tehran’s full support for the Syrian government. Iran has been one of Assad’s principal political and military supporters and has deployed military advisers and forces after 2011 protests against Assad’s rule turned into an all-out war.

Iranian-backed Iraqi militias have deployed in Syria to back the government’s counteroffensive against the insurgents, an Iraqi militia official and a war monitor said Monday.

According to the Syrian Observatory for Human Rights, a Britain-based opposition war monitor, some 200 Iraqi militiamen riding on pickups crossed into Syria overnight through the strategic Bou Kamal crossing. They were expected to deploy in Aleppo to support the Syrian army’s pushback against the insurgents, the monitor said.

Meanwhile, Associated Press video showed armed insurgents at Aleppo's international airport, one of them standing on a Syrian government flag and others tearing down a poster of Assad. Insurgents were also seen mounting abandoned aircraft and walking around airport grounds strewn with weapons and ammunition boxes.

The rebel offensive in Syria has caused concern among neighboring countries that the conflict could spill over. In Iraq, Interior Ministry spokesperson Brig. Gen. Miqdad Miri said security forces have deployed in greater numbers to protect their large border with Syria.

Fidan reiterated Turkey’s support for Syria’s territorial integrity, but suggested that Turkey would not hesitate to intervene against Syrian Kurdish militia groups that Turkey considers to be terrorists if they “exploit the environment of instability.”

“It was a mistake to ignore the legitimate demands of the opposition and for the (Syrian) regime not to sincerely engage in the political process,” Fidan said.

Turkey, he added, "will never, ever allow terrorist organizations that seek to exploit the environment of instability," Fidan said. “We will eliminate any threat to our national security and our people wherever it emerges.”

Turkish President Recep Tayyip Erdogan expressed hope that the instability in Syria would come to an end “in line with the legitimate demands of the Syrian people.” He spoke Monday at a joint news conference with the president of Montenegro.

Both Fidan and Araghchi said Turkey, Iran, and Russia would convene a new three-way meeting to address the conflict in Syria.

"We have decided to hold closer consultations and dialogue, and with God’s permission, we will cooperate to further improve the situation toward peace and stability in our region,” Araghchi said.

Russia, whose intervention in Syria’s civil war on behalf of Assad was crucial in turning the conflict in his favor, has said it will continue to support him.

“We continue our contacts at the appropriate level and analyze the situation,” Kremlin spokesman Dmitry Peskov told reporters Monday. “A position will be formed regarding what is needed to stabilize the situation.”