KOLKATA, India (AP) — Medical staff at an Indian hospital abandoned their patients and fled for safety early Friday as fire and smoke poured through the building, leaving 65 people dead, many from smoke inhalation, government officials said.

As rescuers scrambled to evacuate survivors, police filed a case against the hospital in the eastern city of Kolkata for violating safety procedures and top government officials vowed to hold the hospital accountable for the tragedy.

“It’s a very serious offense, and we will take the strongest action,” Mamata Banerjee, chief minister of the state of West Bengal, said at the scene.

Firefighters on long ladders smashed windows in the upper floors of the AMRI Hospital to pull trapped patients out before they suffocated, while sobbing relatives waited on the street below. Rescue workers took patients on stretchers and in wheelchairs to a nearby hospital.

The fire killed 65 people, most of them patients, police said. Many of them died from suffocation.

The blaze erupted in the building’s basement, and heavy smoke quickly engulfed the hospital. The cause of the fire was not immediately known.

S. Upadhay, a senior vice president of the AMRI hospital company, said there were 160 patients in the 190-bed hospital annex at the time of the blaze.