A bus carrying children and their teachers on a school trip has caught fire in Thailand. Local media outlets say at least 20 people are dead.

An eyewitness made an emergency call shorty after Tuesday noon, reporting that a bus was burning on an expressway in a suburb of the capital Bangkok.

Local police say they believe more than 40 people were onboard the vehicle, including preschool children, elementary and junior high school students and teachers. Reports say 19 of them have been rescued.

An eyewitness told NHK that smoke came out from near the driver's seat and that he also saw flames rising. He said he was scared of a possible explosion.
Police are interviewing people related to the bus operation and investigating the cause of the fire.