ANKARA, Turkey (AP) — Rescue teams recovered another body from a copper mine that collapsed in southeastern Turkey, officials said Friday, raising the death toll to four.

A rescue operation to find 12 miners still missing was underway, but the head of Turkey's crisis management agency, Halis Bilden, said chances of reaching them alive were slim.

"I don't believe that we will be able to reach them alive," Bilden told reporters from the mine site in televised comments. "I cannot say that we have reached signs of life."

The privately-owned mine near the town of Sirvan, in Siirt province caved in late Thursday.

Mustafa Tutulmaz, the governor for Siirt, said authorities think a landslide triggered by heavy rains caused the collapse. However, an investigation had been launched to determine whether the accident may have resulted from negligence, he said.

Families watched as rescue teams searched for the workers who were buried along with trucks and other machines.

In 2014, 301 miners were killed in a fire inside a coal mine in Soma, western Turkey — the nation's worst mining disaster. The tragedy exposed poor safety standards and superficial government inspections in Turkey's mines.