A Thai teenager killed his grandparents before opening fire at his school, where he shot five people dead and took his own life, police have said, in an attack that has shaken a country struggling to deal with gun violence.

Police said the 14-year-old pupil wounded another 22 people in the school ⁠shooting on the outskirts of Bangkok on Friday morning. Nine people were in a critical condition, the Thai health department said.

The suspected attacker fired at least 26 bullets with a gun belonging to his grandfather, and was found with 34 additional ammunition rounds.

Police also said the teenager had killed his grandparents before the attack, which ‌took place at the prestigious Debsirin Nonthaburi school in the Bang Kruai district of Nonthaburi province.

The suspected shooter remained inside the school after reports of the attack emerged, Arsit Sampantharat, the permanent secretary of the interior ministry, told PPTV.

Kiatikhun Verapongpradith, an emergency worker, described arriving as the shooting was ongoing and his team treated students with injuries in the back, chest and arms.

They found a male teacher lying dead on an upper floor of the school, and in another room they found a female teacher with wounds to her chest and arm, Verapongpradith said.

Images from the scene about an hour after the shooting showed people standing outside the school comforting one another while police and first responders were inside the building. It appeared to have been secured, although officials had not publicly confirmed the shooter’s status.

A witness told reporters that students hid in a classroom after hearing gunshots from another building before police officers knocked on the door and escorted them safely from the building.

In the 2025 academic year, the school had about 3,100 students and 147 teachers, according to district authorities.

The school is part of the Debsirin network, founded by the Thai royal family. Its alumni include prime ministers, scholars and writers.

Thailand is known to have the highest rate of civilian gun ownership in south-east Asia, and the Switzerland-based Small Arms Survey in 2017 placed the country 13th globally for small gun possession.

Thailand has seen a series of deadly shootings in the past six years, with children among the victims.

The worst by a single perpetrator in its recent history took place in 2022, when a former policeman ran amok in ⁠a three-hour gun-and-knife attack in the north-east that killed 36 people, including 22 children stabbed as they slept at a daycare centre.

Reuters and the Associated Press contributed to this report