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 kilometres (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 defence 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 an anti-Assad uprising and the unleashing by the regime of a brutal crackdown against dissent in March 2011.

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.

Earlier on Monday, the Syrian Observatory for Human Rights monitoring group reported that a Syrian military helicopter had crashed near the Turkish border.

Observatory director Rami Abdel Rahman said the helicopter had landed on the Syrian side of the border and that rebel fighters had captured one of its two pilots.

The second pilot's fate is unknown, he said.

AFP