At least 14 others were injured, some of the in critical condition. Only ten occupants of the bus could escape through the emergency exit.

Rescue officials said an electric short-circuit sparked the fire that engulfed the entire vehicle in flames within minutes.

The fire started in wee hours of Sunday when most of the passengers were sleeping.

Eyewitnesses said the fire continued to burn for hours leaving only a skeleton of the bus.

They told Aaj News that the bus was travelling at a high speed when the fire broke out and the driver tried to control the speed but the bus hit a van carrying oil. The collision and the oil on the can intensified the fire.

It was one of the luxury buses plying between Islamabad and other major cities.

The dead bodies and the injured were moved to nearby public hospital.