More than 20 children feared dead in Thailand bus crash
Sixteen children and three teachers are reported to have escaped, but 22 pupils and three teachers are still unaccounted for.
Photographs show the bus completely destroyed by the fire. Investigators are said to have been unable to enter the vehicle because of the heat, according to local media.
The bus was carrying the children and teachers returning from a school field trip in the northern province of Uthai Thani.
The country's transport minister said he would look into whether this bus was powered by compressed natural gas.
“This is a very tragic incident,” Mr Suriyahe told reporters at the scene.
“The ministry must find a measure… if possible, for passenger vehicles like this to be banned from using this type of fuel because it’s extremely risky,” he added.