At least three people were injured Friday when a sword-wielding attacker struck a high school in central Sweden, prompting a large-scale emergency response before authorities detained a suspect.

The attack took place at Brinell High School in Fagersta, a town of about 13,000 people. The school has roughly 450 students between the ages of 16 and 20.

Authorities did not immediately disclose the conditions of those injured or provide further details about the detained suspect.

"We received an alarm at 1406 (1206 GMT) about suspected deadly violence and sent all available resources to the school," a police spokesperson told Reuters.

The spokesperson said one person at the scene was later taken into custody and that there was no longer any danger to the public. "IT FEELS UNREAL"

The school had just opened after summer recess and for some students it marked the first day at the senior high school. Local newspaper Fagersta-posten talked to Madelene Jansson outside the school, which her daughter had been attending. "I first got a text message from her that somebody had been stabbed and that police was on its way. Then it all just went off. It feels unreal," she told the paper.

Several other schools and public buildings in Fagersta were also placed in lockdown after the sword attack took place. The Vastmanland county authority said it had adopted high alert status. "We are moving into high alert status to marshal our resources and gain the clearest possible picture of the situation. That will give us the best basis for making the right decisions," Jonas Cederberg, director of health and medical services, said in a statement.

Citing unnamed sources, the daily Expressen said police had shot the suspect in the case, but Reuters could not immediately confirm the report.

The incident comes a year after a school shooting in Orebro, also in central Sweden, when a gunman killed 10 people before turning the weapon on himself, in the worst mass shooting in Swedish history.

The Swedish government is in close contact with the police following Friday's attack, Justice Minister Gunnar Strommer said in a statement to Reuters.

Swedish Prime Minister Ulf Kristersson said police were working intensively on the case and asked everyone to let them and the emergency services work undisturbed.

"Our thoughts are with all those affected," he wrote in a post on social media X.

Social Democrat leader Magdalena Andersson, whose centre-left coalition holds a clear lead in opinion polls ahead of next month's parliamentary election, said that "all of Sweden stands together with Fagersta at this difficult time."