ANKARA, Turkey (AP) — A military helicopter crashed in eastern Turkey on Thursday, killing nine soldiers on board and injuring four others, the Defense Ministry said.

The Cougar type helicopter crashed in a rural area near the town of Tatvan, in the predominantly Kurdish-populated Bitlis province. It was on its way to Tatvan from the nearby province of Bingol when authorities lost contact with it at 2:25 pm (1125 GMT), the ministry said.

The injured soldiers were being evacuated to hospitals, it added.

The ministry described the incident as an accident, but it wasn’t immediately known what caused the crash.

HaberTurk television said the chopper is believed to have crashed in adverse weather conditions, including snow and fog.

There was no immediate information on the soldiers’ identities or ranks.

The location of the crash is in an area where Turkish troops have been combating militants of the banned Kurdistan Workers’ Party, or PKK. The conflict has killed tens of thousands of people since 1984.

The PKK is considered to be a terrorist group by the United States and the European Union.