ISTANBUL — Turkey said Thursday that an airstrike by the Syrian government killed 29 of its soldiers in Idlib, a war-torn province in northwestern Syria that has become the site of an increasingly volatile military confrontation among Ankara, Damascus and Moscow.

The death toll was the highest for Turkish forces in a single day since Turkey began ramping up the deployment of troops to Idlib this month to block a Russian-backed Syrian military offensive. At least 36 Turkish soldiers also were wounded, according to Gov. Rahmi Dogan of Hatay province, who announced the soldiers’ deaths.

Turkish President Recep Tay­yip Erdogan convened an emergency meeting of his top security officials Thursday night, local media reported, amid unconfirmed reports that the Turkish death toll was higher. The Syrian Observatory for Human Rights, a monitoring group, said 34 Turkish soldiers were killed.

The Observatory, as well as the Hatay governor, said the Syrian attack on the Turkish troops had occurred in southern Idlib province, where Turkey maintains military observation posts.

Fahrettin Altun, Erdogan’s spokesman, said Turkey would “retaliate against the illegal regime, which pointed their guns at our soldiers.”

Turkey has been trying to halt a rapid advance by the Syrian army across Idlib province and nearby areas, which have been held by rebels opposing the government of Syrian President Bashar al-Assad. The province is largely controlled by an extremist group that once was formally associated with al-Qaeda.

The Syrian government offensive has sparked a massive humanitarian crisis and sent hundreds of thousands of displaced Syrians fleeing toward the Turkish border. Russia, which is the Syrian government’s principal ally, has carried out airstrikes to aid the Syrian advance and provided Assad’s forces with other military support.

Turkey has called for the restoration of a de-escalation agreement between Ankara and Moscow and threatened to take further military action if Syrian forces do not withdraw from areas they have captured in Idlib. But negotiations between Ankara and Moscow over the past month aimed at securing a cease-fire have repeatedly faltered as the violence has grown more intense.

In recent days, a flurry of Russian airstrikes allowed Syrian forces to capture a swath of territory in southern Idlib. Turkey and its rebel allies, meanwhile, recaptured a city in eastern Idlib that sits at the junction of two strategic highways, Syrian activists said Thursday.

At least 18 Turkish soldiers had been killed in Idlib before the deaths of the soldiers Thursday, according to a tally by the Associated Press. Erdogan said earlier Thursday that three Turkish soldiers had been killed in Idlib. It was not clear whether those deaths were included in the total cited by the governor.

A short memorial ceremony was held for two of the slain soldiers at Hatay’s airport Thursday morning. An honor guard saluted the two coffins, which were resting in the cargo bay of a Turkish military plane. Passengers on a nearby commercial flight, many visibly upset, captured video of the moment on their phones.

The Trump administration has voiced support for Turkey, its NATO ally, as Erdogan’s government wades deeper into the battle for Idlib. Ankara has asked Washington to provide Turkey with the Patriot air defense system, but the Trump administration has refused because of Turkey’s purchase of a Russian missile defense system.

Kay Bailey Hutchison, the U.S. ambassador to NATO, said during a briefing with reporters at the State Department on Thursday that she was unaware of the reports of large-scale Turkish casualties but called it a “big development.”

“I hope that President Erdogan will see that we are the ally of their past and their future. And they need to drop the S-400,” she said, referring to the Russian missile defense system that Turkey acquired.

Hudson reported from Washington.