Turkey said it had downed a Syrian military helicopter on Monday, accusing it of violating its airspace.
A Syrian MI-17 helicopter was detected two kilometers (1.2 miles) inside Turkish airspace at 2:20 pm (1120 GMT), Deputy Prime Minister Bulent Arinc told reporters.
"It was continuously warned by our air defense but as the violation continued, it fell on Syrian soil at 2:25 pm (1125 GMT), having been hit by missiles from our planes," he added.
Arinc said there was no information about the fate of its crew because the helicopter fell on Syrian soil.
Turkey has changed its military rules of engagement in response to repeated gunfire from the Syrian side towards the border areas, Arinc added.
Relations have deteriorated between Damascus and Ankara, who were once close allies, since the outbreak of the Syrian war.
Turkey has since then consistently lobbied for Syrian President Bashar al-Assad's downfall and has deployed NATO Patriot missiles along its border with Syria.