"There were electric scooters parked where the fire started. We don't know if it started because of over-charging and then spread or whether it started elsewhere. That is still being established," Chandana Deepti, deputy commissioner of police in the city, told Reuters.
A detailed investigation into the cause of the fire had begun, she said.
Police and firefighters used cranes and other equipment to rescue those stranded on upper floors of the hotel, even as smoke billowed out of windows of the four-storey building, local media showed.
"Those staying on the first and second floor were overpowered by smoke and the maximum casualties are from that floor," Hyderabad city police chief C V Anand told Reuters partner ANI.