"One of our helicopters was destroyed in an area close to the border due to an unknown reason. Technicians are examining the helicopter at the site," the general staff said in a statement posted on its web site.

Rebels of the Kurdistan Workers' Party (PKK) said earlier they had shot down a Turkish attack helicopter on Saturday in a border region called Cham Chu, near the town of Amadiyah, 50 kilometres (30 miles) northeast of Dohuk.