Two Turkish soldiers were killed and two were wounded in an attack on their armored vehicle in northern Syria, and Turkish forces immediately launched retaliatory fire, Turkey's defense ministry said on Saturday.
"Our punitive fire against terrorist positions is continuing," the statement on Twitter on said.
It said the attack was in the region where Turkey launched the cross-border "Euphrates Shield" operation in 2016 to drive away Islamic State militants and the Syrian Kurdish YPG militia.
Media reports said the attack was in the al-Bab area.
Turkey continues to hold sway in northwest Syria and has a significant military presence there.
Turkey regards the YPG as a terrorist group linked to militants who have fought a decades-old insurgency against the state in southeast Turkey. It has staged several incursions into Syria in support of Syrian rebels to push the YPG from the Turkish frontier.