A Danish man suspected of a bow-and-arrow attack in a small Norwegian town that killed five people is a Muslim convert who was previously flagged as having been radicalised, police say.
Norway's national security agency said the suspect's actions "currently appear to be an act of terrorism."
The man is suspected of having shot at people in a number of locations in the town of Kongsberg on Wednesday evening. Several of the victims were in a supermarket, police said.
"There earlier had been worries of the man having been radicalised," Police chief Ole B. Saeverud said during a news conference.
He didn't elaborate on what was meant by being radicalised.
Norway's domestic security agency, known by its acronym PST, cited various aspects of the attack that also wounded two people in explaining its belief that the suspect's actions "currently appear to be an act of terrorism."
"Attacks on random people in public places are a recurring modus operandi among extremist Islamists carrying out terror in the West," the domestic security agency said.
It added that the suspect "is known to PST from before, without PST being able to provide further details about him."
Ann Iren Svane Mathiassen, the police attorney who is leading the investigation, told Norwegian broadcaster NRK that the suspect will be assessed by forensic psychiatric experts Thursday.
The victims were four women and one man between the ages of 50 and 70, Saeverud said.
Police were alerted at 6.12pm on Wednesday to a man shooting arrows in Kongsberg, some 66km southwest of Oslo. Officers made contact with the suspect but he escaped and wasn't caught until 6.47pm, Saeverud said.
"From what we know now, it is reasonably clear that some, probably everyone, was killed after the police were in contact with the perpetrator," Saeverud said.
Speaking calmly and clearly after his arrest, the suspect told police, "I did this," said Svane Mathiassen. The suspect "clearly described what he had done. He admitted killing the five people," she told The Associated Press
Police have already spoken to between 20 and 30 witnesses who saw the attacker wound and kill his victims, according to Svane Mathiassen.
The bow and arrows were just part of the killer's arsenal. Police are yet to confirm what other weapons he used.
Both the hospitalised victims are in intensive care. They include an off-duty police officer who was inside the store.
Norwegian media reported that the suspect previously had been convicted of burglary and possession of drugs, and last year a local court granted a restraining order ordering him to stay away from his parents for a six-month period after he threatened to kill one of them.
Newly appointed Prime Minister-Jonas Gahr Stoere called the attack "horrific."
"This is unreal. But the reality is that five people have been killed, many are injured and many are in shock," Gahr Stoere told Norwegian broadcaster NRK.
In a statement to the mayor of Kongsberg, Norwegian King Harald V said people have "experienced that their safe local environment suddenly became a dangerous place. It shakes us all when horrible things happen near us, when you least expect it, in the middle of everyday life on the open street."
Norway's worst peacetime slaughter was on July 22, 2011, when right-wing extremist Anders Breivik set off a bomb in the capital, Oslo, killing eight people. Then he headed to tiny Utoya Island, where he stalked the mostly teen members of the Labor Party's youth wing and killed another 69 victims.
Breivik was sentenced to 21 years in prison, the maximum under Norwegian law, but his term can be extended as long as he's considered a danger to society.
Australian Associated Press