A Turkish soldier deployed on the border with Syria was killed early on Thursday by fire from Syrian territory, the Dogan news agency reported.
The soldier, 21, was standing guard in the Reyhanli district of the Hatay region of southern Turkey when he was hit by fire from the Syrian side of the border.
Despite efforts to save him, the soldier died in hospital, Dogan said, quoting a statement from the regional governor.
Two Turkish soldiers have been killed since late July in fire from Syria in incidents blamed on jihadists from the Islamic State (IS) extremist group.
Another soldier was abducted on September 1 and has not been heard of since.
It was not immediately clear which of the many groups fighting in northern Syria were behind in the current incident.
After months of hesitation, Turkey has fully joined the US-led coalition against IS, carrying out air strikes against its targets for the first time.