The police chief in the town of Kongsberg announced the deaths at a news conference.
"The man who carried out the act has been arrested by the police, and there is no active search for more people.
"Based on the information we have, there is one person behind this," police vhief Oeying Aas said.
He said there were several deaths but did not offer any details.
Police were alerted to the attack around 6:30pm and arrested the suspect about 20 minutes later.
The community is 41 miles southwest of Oslo.
According to police, the suspect walked around the city shooting at people with arrows.
The man has not been questioned yet, and his motive was unknown, Mr Aas said.
According to the BBC, residents were said to have been ordered to stay indoors.
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