Five people have been killed and two others – including an off-duty police officer – were injured in a series of bow and arrow attacks in Norway, according to police.

The incidents took place in the town of Kongsberg, 51 miles (82km) southwest of the capital, Oslo.

A suspect has been apprehended by police, who believe he allegedly acted alone.

There was a confrontation with officers and the man tried to run away before he was arrested, the police chief said.

Two other people were wounded and are in intensive care, including an officer who was off duty and inside the shop where the attack took place, police said.

The attacks are related to a Coop Extra supermarket in the town centre and Coop spokesman Harald Kristiansen said: “We can confirm that there has been a serious incident in our store and that none of our employees are physically injured.

“We are now concerned with following up our employees, and beyond that, we refer to the police investigation.”

Police were called to the incident, in the centre of Kongsberg, at 6.30pm on Wednesday with additional resources sent from other areas, including Oslo.

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Police chief Oeyvind Aas told a news conference: “I can, unfortunately, confirm that several people have been killed and injured.

“A man was apprehended at 6.47pm. From the information we have at the moment, one person committed this act alone. He hasn’t been questioned yet so it’s too early to say what the motive was.

​”There is major police activity in the area because there are many crime scenes.”

He declined to comment on the number of casualties and said he could not comment on whether the man was known to the police.

The suspect has now been taken to Drammen police station.

Chief Aas added: “It is natural to consider whether it is an act of terrorism. He has not been questioned, and it is too early to come to any conclusion.”

Asked if he could confirm that a police officer had been shot in the back, he replied: “I can’t answer that question”.

The attacks took place over a “large area” of Kongsberg, a municipality of around 28,000 people in southeastern Norway, police said.

“There is still a lot of police activity in the area. This is because the perpetrator has moved across a large area, and we are now working, among other things, to secure clues and gather as much information as possible about what has happened,” said Chief Aas.

The injured people have been taken to hospital and Kongsberg council’s crisis team is giving help to those who need it.

Unni Grondal, Oslo police spokesperson, said: “We are helping with national assistance resources such as police helicopters, bomb squads, and crews from the emergency response troop.”

Norway’s minister of justice and public security, Monica Maeland, has been informed and is closely monitoring the situation.

Local media reported a large area on the west side of the town had been cordoned off, with investigations now under way.

British ambassador to Norway, Richard Wood, wrote on Twitter: “Police confirming that five people have been killed in #Kongsberg and several injured including a policeman. A shocking incident. Sincere condolences to those affected.”

Norwegian police – who normally do not carry guns – have been ordered to temporarily arm themselves.

The Norwegian police directorate said: “This is an additional contingency measure. The police do not yet have any concrete indications that there is a change in the threat level in the country.”

Acting Prime Minister Erna Solberg called the attack “gruesome” and said it was too early to speculate on the man’s motive.

She added: “The perpetrator has carried out horrific acts against several people. The incident has shaken us.”