Most of the victims were patients who were trapped after the flames spread through the AMRI hospital.

The fire started in the multi-storey hospital's basement, where flammable materials were stored. Firefighters took five hours to control the blaze.

Six board members of the hospital have been arrested.

They include hospital co-founders SK Todi and RS Goenka.

West Bengal Chief Minister Mamata Banerjee said the licence of the six-storey hospital in Dhakuria in the southern part of the city had been cancelled.

She said the fire was an "unforgivable crime" and that those responsible would be given the harshest punishment.

A Upadhay, a senior vice-president of the AMRI hospital company, told Associated Press there were 160 patients in the 190-bed hospital.

A spokesman for Manmohan Singh said the Prime Minister had "expressed shock and anguish over the loss of lives".