At least 20 people are feared dead in a fire that broke out in a hospital in the eastern Indian city of Calcutta (Kolkata), officials say. At least 40 patients are reported to have been trapped after the flames spread through the AMRI hospital in the southern part of the city. The fire broke out in the basement of the hospital early on Friday, officials say. Fire engines fought the blaze for five hours before bringing it under control. Rescue workers are trying to reach the upper floors of the six-storey hospital in Dhakuria to rescue patients. "Patients have suffocated on the fumes. Many have lost their lives," West Bengal Urban Development Minister Firhad Hakim told reporters. A number of patients have been rescued, and moved to other hospitals. "We have shifted 50 patients to an adjacent hospital. The situation is grim at the moment," fire brigade chief Gopal Bhattacharya told the AFP news agency. Mr Hakim said the fire broke out in the basement of the hospital, which was being used as a store for flammable items. The fire spread swiftly to the upper floors of the private hospital. TV pictures showed patients in gurneys being rescued and distraught relatives of trapped patients. Thick smoke was coming out of the lower floors. One rescued patient said: "The attendants woke me up and dragged me down the stairs. I saw 10-15 patients at the top of the stairs trying to get down."