Seven climbers were killed and two others critically injured after a wildfire broke out on Mount Lawu on Indonesia’s Java island, an official said.

Rescuers found the seven bodies on Mount Lawu on Sunday and Monday, said Agung Lewis, the head of the disaster management agency in Magetan regency.

Two other hikers were still being trapped, he said,

Agung said it was not clear what sparked the fire.

The spokesman for the National Disaster Management Agency, Sutopo Purwo Nugroho, said late Sunday that the blaze was apparently triggered by a campfire that had not been fully extinguished.

The 3,265-meter mountain, a popular hiking destination, is a dormant volcano which last erupted in 1885.