As many as 17 children and their teacher were killed Saturday when a fault gas cylinder exploded on a school bus in eastern Pakistan.
Police in the city of Gujrat, about 200km southeast of Islamabad, said the victims burned to death in the fire, and several other children were injured and hospitalized.
The bus driver is reported to have survived.
More from GlobalPost: Autistic student handcuffed on school bus ‘for his own safety’
The children, between the ages of four and 10, were just a few kilometers from their school when the accident happened. Police said the fire appeared to have been caused by a spark when the driver of the dual-fuel minibus switched from gas to natural gas.
Two of the surviving children escaped from a window in the back of the bus and told reporters they smelled gas before the fire broke out.
One boy said he could hear the other children shouting: "Brother, save us, save us. We are burning."
"I took a huge stick and broke the glass. I tried to save them but I couldn't," he said.
Compressed natural gas is used in millions of vehicles in Pakistan because it is cheaper than diesel and gas. Many vehicle explosions have been blamed on faulty cylinders used to contain the fuel.