Norwegian police said Friday they had arrested a 28-year-old man suspected of stabbing two police officers and seriously wounding them in the small southern town of Vennesla.
The motive for the attack was not immediately known. A police spokesman told broadcaster NRK that there were "still some bricks missing" in its investigation into the man's actions.
Hospitalised in the neighbouring town of Kristiansand, the two victims are "in serious condition but their lives are not in danger," a local police spokesman told TV2 television.
The attack took place in the Vennesla town centre, where police arrested the suspect after launching a massive search.
As of Saturday, the arrested man was being held in a psychiatric unit. Police said that he has a previous conviction for a knife-related offence six years ago.
Police said the two victims were plainclothes officers but were wearing symbols denoting them as policemen.
This type of violence is extremely rare in the normally tranquil country that has low crime rates.
Norwegian police do not normally carry service weapons, but they have been temporarily authorised to do so for the past year because of the heightened risk of a terrorist attack.