Twenty elderly people were killed when a fire broke out on a coach as it travelled down the A2 motorway near Hanover in northern Germany on Tuesday night. Police suspect that the fire was caused by a passenger sneaking a cigarette in the bus toilet.

Police say that the fire broke out at 8.45 p.m. (CET) on Tuesday evening after the toilet door was opened and flames shot out, quickly engulfing the vehicle.

It is thought that some of the elderly passengers who perished had walking disabilities and were unable to escape in time. The driver, who had managed to pull over, and 12 other passengers managed to flee the burning bus. Many were injured and three of them suffering serious burns.

"I just saw smoke and then I got closer and closer and realized that a coach was on fire," Nadia Possberg, an eyewitness who was driving on the motorway, told local television. "It was terrifying."

At least 150 firemen and police fought to put out the blaze, which caused the motorway to be shut down until early on Wednesday morning. The police told reporters that the bus had not collided with any other vehicle or object and they also doubt it was a technical fault. The wreckage of the bus with the 20 bodies on board was taken to Hanover overnight.