Seventeen Turkish soldiers have died after their helicopter crashed in southeastern Turkey in bad weather, an official has said.
The Sikorsky aircraft came down on Herekol mountain, in the Pervari district of Siirt province, according to Siirt governor Ahmet Aydin.
The victims were members of gendarmerie special forces and there were no survivors on board, he said.
Authorities are investigating the cause of the crash which reportedly happened in thick fog.
The helicopter was transporting troops to Pervari, where the Turkish army has been involved in operations against Kurdish rebels for three days, security sources told AFP.
The military has been on Herekol mountain in an attempt to flush out militants from outlawed separatist group the Kurdistan Workers Party (PKK) who have hideouts there.
Since the summer, there has been an upsurge in PKK attacks in southeast Turkey, particularly in the Hakkari region.
Turkish jets and helicopters have pounded PKK positions along the border with Iraq and Iran for three days, killing 42 militants, Hakkari's governor said.
Last month, a Sikorsky crashed in southeastern Diyarbakir province after it hit power lines, killing one soldier and wounding seven.