Turkish military officials say they have lost contact with two of their soldiers in northern Syria, where they are engaged in an offensive against so-called Islamic State.
IS claimed via its news agency that its militants had captured two Turkish soldiers in al-Dana village near al-Bab in northern Syria.
Turkey has not commented on the claim.
The Turkish military is leading an offensive to clear IS and Kurdish forces from the strategic al-Bab town.
Since launching a ground offensive against IS in September, Turkey has become an increasing target for the militants.
Jihadist cells are believed to have carried out several bombings in the country over the past year.
Recently, an audio recording, purportedly by the leader of IS, was released in which he called on his fighters to attack Turkey and its forces in Syria and Iraq.
The BBC's Mark Lowen in Istanbul says that although the Turkish government currently has broad support for its military offensive in Syria, that support could wane if its army sustains more losses.
IS is believed to have captured a Turkish soldier in the summer of 2015, with his location still unknown.