Five other soldiers were wounded, the defence ministry said on Twitter, adding that the Turkish military retaliated on the designated targets.

"According to different sources in the region, over 50 regime elements, five tanks, two armoured personnel carriers, two armoured pickups and one howitzer were destroyed," the ministry said in another tweet.

Turkey has 12 observation posts in Idlib as part of a Turkey-Russia deal, but Ankara's forces have come under attack this month from Syrian regime forces.

Turkish President Recep Tayyip Erdogan's top press aide, Fahrettin Altun, accused the Syrian regime of responsibility for the latest deaths.

"Our soldiers, who are in Idlib to secure peace and managed humanitarian aid activities, were attacked by the regime," Altun said on Twitter.

Just before the ministry's statement, the Russian defence ministry urged Turkey to stop supporting "terrorists," saying Thursday that Russian planes carried out air strikes against armed groups backed by Ankara.

Regime supporter Moscow has previously accused rebel backer Ankara of failing to act against "terrorist groups in Idlib", which Turkey denies.

Earlier this month, 14 Turks were killed by the regime in two separate attacks in the last rebel-held bastion, where Damascus backed by Moscow has pressed an offensive.

Hundreds of thousands of people have been forced to flee their homes since December in the largest displacement since the civil war in Syria broke out almost nine years ago.

The attacks on Turkish forces have caused strains between Moscow and Ankara, with Turkey urging the regime to pull back by the end of February from behind Turkey's military posts in Idlib.

Erdogan warned Wednesday of an "imminent" operation if Damascus did not heed his call.