A fire has killed more than 70 people at a private hospital in the eastern Indian city of Kolkata.

Authorities say the blaze swept through the AMRI Hospital early Friday in the capital of West Bengal state.

Local television channels showed patients being rolled out on stretchers and distraught relatives waiting outside the hospital as smoke engulfed the multi-story building.

A senior vice president at AMRI said 73 people were killed in the fire, including three staff members. He said there were 160 patients at the hospital at the time of the blaze.

It was the second fire at the facility in three years.

West Bengal Chief Minister Mamata Banerjee has begun proceedings to cancel the hospital's license. She promised a full investigation into the incident, after government officials alleged that some hospital staff fled the scene when the fire broke out.

Banerjee also said action would be taken if fire prevention standards were found to be below-standard.

But AMRI's senior vice president said the hospital followed strict fire safety measures. He promised monetary compensation to victims' families.

Firefighters worked to bring the blaze under control and rescue those still trapped inside the building, after maneuvering narrow surrounding streets to reach the Kolkata hospital.

Officials say the fire broke out in the hospital's basement, where chemicals were stored.