Syrian state media said a surveillance drone was shot down by Turkish military jets on Saturday, which Turkey said had violated its airspace.
NATO member Turkey, an outspoken critic of Syrian President Bashar al-Assad, has a 900-km border with Syria and frequently scrambles jets to its frontier amid concerns aircraft have violated its air space.
A Turkish military official said two F-16 fighters flying out of Incirlik base in southern Turkey had opened fire on a target, but he was unable to give details about the target.
Eyewitnesses in Turkey's Hatay province, which borders Syria, reported seeing an aircraft fired upon by jets and break apart in the air. News channels said it landed in Syria.
The Turkish military has stepped up security in province at the border following the incident, security sources said.
Assad has said Turkish support was a key factor in helping militant Islamist insurgents seize the northwestern Syrian city of Idlib earlier this year.
Turkey denies that allegation and any suggestion it has delivered arms to Islamist militants fighting to overthrow Assad.