Ahmet Aydin, governor of the southeastern province of Siirt, blamed heavy fog for the early-morning crash, Hurriyet Daily News reported.
The Sikorski helicopter carrying the soldiers crashed into rocks in the Pervari district of Siirt, he said.
"We have reached the bodies," Aydin said. "The cause of the crash is a hundred percent the fog."
Meanwhile, officials said Friday Turkish armed forces had killed 42 members of the outlawed Kurdistan Workers' Party in operations that began Wednesday in the eastern province of Hakkari.
The Hakkari governor's office said in a statement that weapons, including rocket launchers, mortars and explosives, were seized.