A 37-year-old Danish citizen has been arrested and charged after five people were killed and two others injured in an attack using a bow and arrows in the Norwegian town of Kongsberg, police said.

The suspect lived in the town and was transported to the nearby town of Drammen on Wednesday night, the police said in a statement issued early on Thursday.

Police were interrogating the suspect and he was talking, his defence lawyer said. “He is cooperating and is giving detailed statements regarding this event,” his lawyer, Fredrik Neumann, told public broadcaster NRK.

Neumann said his client was “deeply affected” and would be remanded in custody later on Thursday. He declined to comment further beyond saying the suspect’s mother was Danish, but it was not known whether he had ever lived there.

Øyvind Aas, the police chief in Kongsberg, about 70km south-west of the capital, Oslo, told a press conference earlier on Wednesday night that the alleged attacker had been arrested and “according to our information, is the only person implicated”.

Aas said there had been “a confrontation” between officers and the assailant, but he did not elaborate. Two people were in intensive care, including an off-duty police officer.

Aas declined to comment on press reports that a police officer had been shot in the back. He said the attacks happened over “a large area” of the town and several crime scenes were involved.

The acting prime minister, Erna Solberg, described reports of the attack as “horrifying” and said it was too early to speculate on the man’s motive.

“I understand that many people are afraid, but it’s important to emphasise that the police are now in control,” she told a news conference.

The prime minister-designate, Jonas Gahr Støre, who is expected to take office on Thursday, called the assault “a cruel and brutal act” in comments to Norwegian news agency NTB.

The alleged attacker’s motive was not yet clear, Aas said, but police were not ruling out terrorism. “One person has performed these actions alone,” he said. “It is natural to consider whether it is an act of terrorism. But the man has not been questioned and it is too early to come to any conclusion.”

NRK said police in Kongsberg, a municipality of about 28,000 people, received reports at 6.13pm local time that a man was walking around the town centre firing a bow and arrow.

A woman who witnessed some of the attack, Hansine, told TV2 she had heard a disturbance, then saw a woman taking cover and “a man standing on the corner with arrows in a quiver on his shoulder and a bow in his hand”.

“Afterwards, I saw people running for their lives. One of them was a woman holding a child by the hand,” she said.

A “large number” of police, as well as helicopters, dogs and armed response teams secured the area soon afterwards, Aas said, and the suspect was arrested about 30 minutes later after a brief confrontation with officers.

The shooting appears to have started in or near a Coop store in the city centre where there were several casualties, Norwegian media reported, citing regional government officials who said details were “still very confused”.

A Coop spokesperson, Harald Kristiansen, told NRK there had been “a serious incident in our store” but no employees were among the injured. “We are providing assistance to our colleagues and helping police with their investigation,” he said.

“A lot of resources were sent from several places, including Oslo police district, the bomb squad, national police and emergency response teams,” Aas told journalists. “There is still a lot of police activity across the area. They are securing the various crime scenes … and have many witnesses to interview.”

A woman, who lived near the Coop store said she had heard alarms as she was walking home. “I saw a group of police officers, including one who held several arrows in his hand,” the woman, Marit Hoefle, told Aftenposten newspaper.

Kari Anne Sand, Kongsberg’s mayor, told VG newspaper the attack was “a tragedy for all those involved. I have no words”. Sand said a crisis team had been installed in a hotel to support those affected. “We are doing all we can,” she added. “Right now it is a chaotic situation and there are a lot of rumours.”

Shortly after the attack Norway’s national police directorate said it had ordered officers nationwide to carry firearms. Norwegian police are normally unarmed but officers have access to guns and rifles when needed.

“This is an extra precaution. The police have no indication so far that there is a change in the national threat level,” the directorate said in a statement.

Agence France-Presse and Reuters contributed to this report