"What a shame I have to say that the death toll has risen to 22," Rahmi Dogan, the governor of Hatay in Turkey which sits on the border with Syria, said in televised remarks. He earlier said nine soldiers were killed in the air strike.

The governor said that soldiers injured in the air strike had been brought back to Turkey for treatment but did not give a figure.

Earlier Turkish President Recep Tayyip Erdogan held an extraordinary meeting on the situation in Idlib after the attack, at his presidential complex in Ankara.

The security summit was attended by Defence Minister Hulusi Akar, Foreign Minister Mevlut Cavusoglu, the Chief of Staff General Yasar Guler and spy chief Hakan Fidan, NTV broadcaster said.

The Turkish presidency confirmed the meeting lasted two hours but did not say what the outcome of the talks were.

When there were unconfirmed reports of heavy casualties earlier, Anadolu and other media reported that the Turkish military had "neutralised" 1,709 regime elements.

The media also listed dozens of tanks, helicopters and armoured vehicles belonging to regime elements which were destroyed by Turkish forces, quoting anonymous Turkish security sources.

Turkey has 12 observation posts in Idlib, the last rebel-held bastion, under a 2018 deal with Russia.

But President Bashar al-Assad's regime has pressed an offensive backed by Moscow air strikes, killing hundreds and forcing hundreds of thousands to flee their homes.

Erdogan has repeatedly warned the regime to withdraw from Turkish posts before the end of February, threatening an "imminent" operation if Damascus did not heed the warning.

Cavusoglu spoke to NATO secretary general Jens Stoltenberg on the phone, a Turkish diplomatic source said early Friday without giving further details.

The number of Turkish security personnel killed in Idlib this month is now 42.

There has been an escalation in tensions after Ankara threatened to attack Damascus, with multiple rounds of talks between Turkish and Russian officials to find a way forward. The latest negotiations were on Thursday.

Jihadists and Turkish-backed rebels re-entered Saraqeb earlier on Thursday, a key crossroads town in Idlib that they had lost earlier this month.