STOCKHOLM, Sweden (AFP) — One person died and three were wounded after a sword-wielding attacker entered a high school in the town of Fagersta in central Sweden Friday, police said, adding the suspect had been arrested.

Local police chief Tommy Alriksson told journalists that one person had been found dead after police entered the school, having shot and arrested the assailant.

“Our current assessment of injuries is that there are three wounded people and one deceased,” Alriksson told journalists, adding that two had been seriously wounded and a third had lighter injuries.

Alriksson said the arrested suspect was an 18-year-old man. Police were working on establishing a motive, but that they had no reason to believe there were multiple perpetrators, he added.

“It is a very serious and deeply shocking incident,” Fagersta mayor Asa-Marta Sjostrom told reporters alongside Alriksson.

Regional healthcare director Jonas Cederberg told Agence France-Presse earlier that two “seriously wounded” people had been admitted to hospital.

The two were boys between the ages of 12 and 17, and one of them was in emergency surgery though both were in a stable condition, the healthcare authority said on its website.

The Fagersta municipality said in a statement early Friday afternoon that “an assailant armed with a sword has entered Brinellskolan and wounded several people.”

Police said they had received reports of the attack just after 2 p.m.

Students, just back from their summer holidays, were in lockdown at the school and several other nearby schools for more than three hours before being let out.

Swedish broadcaster SVT reported that the perpetrator had a previous assault conviction and wore a helmet and carried a sword — reminiscent of an October 2015 school attack in the western town of Trollhattan in which a sword-wielding 21-year-old killed three people in a racially motivated attack.