RUDRAPRAYAG, India (AP) — Rescuers in northern India are working to save more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off and sent a wall of water and debris rushing down a mountain.

More than 2,000 members of the military, paramilitary groups and police have been taking part in search-and-rescue operations in the northern state of Uttarakhand after Sunday’s disaster.

The incident has killed at least 18 people, left 165 others missing, and damaged dams and homes downstream.

Officials said the focus now is on saving 37 workers stuck inside a tunnel at one of the affected hydropower plants.

Excavators had been brought in the help with the efforts.