NEW DELHI, May 8 (Xinhua) -- Two people were charred to death and one suffered critical burn injuries on Tuesday after an ambulance caught fire in Indian capital city New Delhi, police said.

The ambulance caught fire in Sheikh Sarai area of the city.

"Two persons were charred to death while in sleep inside an ambulance here," a police official said. "The duo was sleeping at the back seat of the ambulance. The third person who was sitting on the front seat of the vehicle suffered critical burn injuries."

The injured has been sent to Safdarjung hospital for the treatment.

Reports said people sitting inside other ambulances parked near the ambulance managed to come out and were saved.

The reason behind the fire was not known.

Reports said mosquito-repelling incense was smouldering inside the ambulance and heavy winds were blowing outside when the vehicle caught fire.

The ambulances belonged to a private company and were parked outside a hospital in Sheikh Sarai.

Police have registered a case and ordered investigations into the incident.