"Two causalities so far and most probably they died after inhaling carbon monoxide or suffocation," said Amitabh Chakrabarty, officer-in-charge of the disaster management team.
The hotel is located in an upmarket area just metres away from US Consulate and the British Deputy High Commission in Kolkata.
According to initial reports, the fire started in the kitchen of the hotel and then spread to other parts of the hotel with guests making a desperate escape. Several guests climbed down from windows after tying bedsheets to the window.
The fire broke out at around 3:00 am and raged on for around three hours. It was finally put out at dawn.
"We heard people screaming for help. We arranged for them to escape from the building. Some people jumped from the window to safety," Surajit Jana, an eyewitness told NDTV. "It seemed that the fire alarm and sprinklers did not work," Mr Jana added. Mr Jana works in the adjacent building and rushed to the spot when he got news of the fire.
"We are investigating how the fire the broke out and why it could not be controlled. We have just completed a preliminary study. We have registered an FIR under provisions of the fire safety law," DG (Fire) Jagmohan told NDTV after inspecting the hotel premises.
As firemen fought the blaze for three hours on Ho Chi Minh Sarani it brought back memories of the 2011 AMRI Hospital fire in which 92 people were killed, many of them by suffocation. The glass encasing and central air conditioning made things worse for the hotel, like it did for the hospital.