A student opened fire at a high school outside Bangkok on Friday, killing at least six people and wounding several others, police said.

The shooting took place at Debsirin Nonthaburi School in Nonthaburi province, northwest of the capital, Royal Thai Police spokesperson Trairong Piwpan told The Associated Press.

A witness told reporters that students hid inside a classroom as they heard gunshots coming from another building. Police officers later knocked on the door and escorted the students out of the building.

About an hour after the shooting, people gathered outside the school, comforting one another, while police and first responders moved around inside the premises.

Authorities provided conflicting casualty figures that could not immediately be reconciled.

Trairong told broadcaster Channel 3 that the shooter was hospitalized in serious condition and that 15 other people were injured, including two in critical condition. He said three teachers and three students were killed.

Health Minister Pattana Promphat said 22 people were injured, nine of them critically. Some of the injuries were caused by falls, and it was not immediately clear how many people were shot.

Deputy Interior Minister Polapee Suwunchwee told reporters at the scene that five teachers had died. He also said the shooter had killed his two grandparents at home before going to the school and later died at a hospital.

Trairong said the motive was still under investigation. He said the gun was believed to have been taken from a member of the student's family.

Prime Minister Anutin Charnvirakul expressed condolences to the victims and said he had instructed relevant officials to provide care and assistance to those affected.

In February, a 17-year-old stole a gun from police and opened fire at a public high school in southern Thailand, briefly taking people hostage during a two-hour attack that killed one person and injured two others.

In 2023, a 14-year-old boy was accused of carrying out a shooting at a major shopping mall in Bangkok.