They would still need to determine whether any arson attack stemmed from conflicts of interest or was politically motivated by those with intent to cause a public disturbance in protest at the September 19 coup.

An initial investigation found that the blaze broke out on Tuesday evening from a switchboard panel inside an auditorium on the second floor of Ban Kham Pom School in Samrong district. No casualties were reported.

Two buildings in the school compound were burned down, causing damage estimated at Bt900,000.

A report initially concluded that many computers, air conditioners and a television set being turned on at the same time could have led to an electrical short-circuit. The school's wiring dates back to when it was built 20 years ago.

The school has 200 pupils and provides classes from kindergarten to sixth grade.

Senior education official Theerasak Kaewyong said a temporary shelter would be built to accommodate classes for the coming school semester on November 1. A Bt3-million budget is being sought to build a permanent building to replace the gutted ones.

Theerasak said he had ordered all schools in Ubon Ratchathani and neighbouring provinces under his jurisdiction to heighten security measures to prevent possible fires.