In the city center of Oslo, the Norwegian police shot a man armed with a knife.
The suspect threatened several people in the Bislett district on Tuesday morning, the police said.
A police officer was injured when the officers tried to arrest the attacker.
The police initially gave no information about the identity of the attacker and his possible motive.
"We are not ruling out any motives, but at the moment there is nothing to suggest that it was a terrorist attack," police commissioner Egil Jorgen Brekke told journalists.
The tabloid "VG" reported that the attacker was a 30-year-old Russian who stabbed a man in 2019.
He then had to seek psychiatric treatment.
Recordings on the online networks showed the man standing with a bare torso and a large knife in front of a shop.
A police car pulled up to him and pushed him against the wall to stop him.
The attacker then opened the passenger door and leaned inside the car.
The man also attacked the police with his knife, the head of the police operation, Tore Solberg, told journalists.
The police then shot the attacker.
He died of his injuries in the hospital.