A bow-and-arrow attack in which a Danish convert to Islam is suspected of killing five people in a Norwegian town appears to have been an "act of terror," police say.
Investigators named the suspect as Espen Andersen Braathen, a 37-year-old living in the Kongsberg municipality where the attacks took place on Wednesday evening.
A police lawyer told Reuters that Braathen had acknowledged killing the victims.
His lawyer confirmed only that Braathen was co-operating with police and giving a detailed statement.
Police had been concerned about signs of radicalisation in the suspect before the attacks, carried out with a bow and arrow and other weapons, a senior officer said.
Flags flew at half-mast across Kongsberg after the deaths of four women and a man, all aged between 50 and 70.
Three others, including an off-duty police officer, were wounded.
"The events at Kongsberg appear at the moment to be an act of terror," the PST security police said in a statement, adding the investigation would determine the motive.
Regional police chief Ole Bredrup Saeverud said the suspect had converted to Islam.
"Police have previously been in contact with the man in relation to trouble connected to radicalisation. We haven't registered anything in regards to him in 2021, but previously," Mr Saeverud told a news conference.
The head of Norway's PST security police, Hans Sverre Sjoevold, said Braathen had a history of being "in and out" of health institutions.
The head of the Norwegian Police Security Service, Hans Sverre Sjovold, speaks during a press conference about the killings at Kongsberg. Source: AAP
Determining whether the attack was an act of terrorism or the result of a psychiatric issue "will be a vital, important part of the investigation," he told Reuters.
The method of the attack, said Sjoevold, was similar to many politically motivated attacks carried out in Europe in recent years.
"The use of knives, public places... The police are not present, so they can carry out the... attack. That's quite typical for these operandi," he told Reuters.
On Wednesday, Kongsberg resident Markus Kultima, 23, who works in a beer shop, witnessed parts of the attack.
"I saw a man come walking with an arrow in his back," Mr Kultima told Reuters.
He said it was the off-duty officer who told him to head home.
Braathen was in custody and was believed to have acted alone, police said.
Police investigate sites connected to the attack in Kongsberg, Norway. Source: AAP
A court will decide on Friday how long police can keep him in custody.
Police attorney Ann Iren Svane Mathiassen told Reuters: "He has told us that he has killed them and he has explained himself in detail about what happened... He admits to the facts of the case but we haven't asked him yet about the question of guilt."
She said police wanted a psychiatric evaluation to determine whether he is fit to stand trial and that those killed "appear to be random victims".
A relative of the suspect, speaking on condition of anonymity to Danish newspaper Ekstra Bladet, described him as mentally ill and said the family had suffered threats for several years.
Prime Minister Jonas Gahr Stoere, on his first day in office after winning an election last month, said his thoughts were with the people of Kongsberg, the victims and "those who live with the shock".
He told a news conference the attack highlighted shortcomings in Norway's psychiatric care, with "one in four or one in five" people who are referred for treatment being turned down.
