Indian officials have charged six staff members of a Kolkata hospital with culpable homicide, following a fire at the facility that killed at least 90 people.

Authorities have also pulled the license of AMRI Hospital which was rated recently by an Indian magazine as one of the Kolkata's best hospitals.

Officials say the blaze swept through AMRI 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 consumed the building. Many of the victims died in their beds from suffocation caused by the thick, choking smoke.

West Bengal Chief Minister Mamata Banerjee has promised a full probe into the incident, after government officials alleged some hospital staff fled the scene when the fire broke out.

She said action would be taken if fire prevention standards were found to be below standard.

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

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

A senior official at the hospital says there were 160 patients at the facility at the time of the blaze, which broke out in the hospital's basement where chemicals are stored.