ISTANBUL (AP) — Kurdish militants have claimed responsibility for a Turkish military helicopter crash that killed all 13 personnel on board two days ago near the Turkey-Iraq border.

The People's Defense Forces or HPG said in a statement Friday that its units fired at the Cougar helicopter Wednesday in the border province of Sirnak. The statement said that "the hit helicopter crashed as it tried to move away."

The HPG is the armed wing of the Kurdistan Workers' Party, which has waged a three-decade-long insurgency against the Turkish state. The war has led to an estimated 40,000 deaths and a two-and-a half-year cease-fire collapsed in the summer of 2015.

The Turkish military said the crash was an accident, with initial information indicating that the helicopter had hit a high-voltage transmission line.