Four people were killed and 15 others injured as a gas cylinder in an ambulance exploded following a collision with a bus in Savar on Aricha highway early Thursday.

Savar Highway Police OC Sougatul Alam said the ambulance caught fire around 2am after being hit by a bus in front of Rajfulbaria Police Town and the blaze engulfed two buses.

“Four passengers of the ambulance died and he bodies could not be identified as those were fully burnt,” he said. The injured were rescued and admitted to a hospital for treatment. Police said the death toll may rise further.

The fire service officials said that the fire broke out due to the explosion of a gas cylinder in the ambulance.