Police first received word of an attack in the town of Kongsberg, south-west of the capital Oslo, at around 18:13 local time (16:13 GMT).
Chief Oeyvind Aas said a suspect had been caught and seemed to have acted alone, but the reasons for the attack are still unknown, so a terrorist background cannot be ruled out.
It’s natural to consider such a possibility, but it’s too early to come to a conclusion, Aas said.
The attacker is said to have launched the assault inside a Coop Extra supermarket on Kongsberg’s west side. One of those injured was an off-duty police officer who was in the shop at the time.
After the attacks, the Police ordered their agents to be alert throughout the national territory and to carry firearms.
Prime Minister Erna Solberg said reports of the incident had been ‘horrifying’, noting that the tragedy shook Kongsberg and the entire country.
On the other hand, Labor leader and Solberg’s Deputy Jonas Gahr Støre condemned ‘the cruel and brutal attack’ and mourned the loss of innocent lives.
My thoughts are with the victims, their families, Police, health personnel and the first responders, he pointed out.