The shooting was first reported at around 10 a.m. local time.

According to preliminary reports by the Bangkok Post, one of the victims was a teacher at the school. Ten other people sustained injuries in the incident.

The suspected gunman, reportedly an eighth-grade student, is believed to have barricaded himself on the third floor of the school's pink building, the Bangkok Post reported.

Some media reports said the suspect has killed himself.

Authorities rushed to the scene and launched an operation to secure the campus and investigate the incident.

The shooting occurred at Debsirin School, a well-known secondary school with branches across Thailand. The original Debsirin School in Bangkok was founded by King Chulalongkorn in 1885, according to the BBC.

Authorities have urged the public to stay away from the school as the situation remains under investigation.