OSLO — A man armed with a bow and arrow went on a rampage in a Norwegian town outside Oslo on Wednesday, killing and wounding several people, the authorities said.

The attack took place in Kongsberg, a town of 26,000 people about 50 miles southwest of Oslo. A suspect was reported to be in custody.

“The information we now have, this person carried out these actions alone,” the police chief, Oyvind Aas, told reporters.

The attack began shortly after 6 p.m., when the assailant began making his way through the center of the town. Residents were urged to seek shelter inside. A half-hour later, a suspect was in custody, the police said.

Across the country, the Norwegian police, who ordinarily are not armed, were given authorization to carry weapons “due to the serious incident in Kongsberg,” the authorities said in a statement late Wednesday. They described it as a precaution.

“The police currently have no concrete indications that there is a change in the threat level in the country,” the statement said.

But the attack left the country on edge.

“The incident has left us all shaken,” said Prime Minister Erna Solberg. “The news is terrifying. I understand that people are getting scared.”

The authorities did not immediately release information about the suspect.

“It is natural to consider if it is a terror event,” Chief Aas said at a news conference, adding that it was “too soon to say for sure what the man’s motivation is.”

Prime Minister Solberg made a similar point.

“I emphasize that we do not know if it is terror or not.” she said.

The assailant ranged over a broad swath of the city, leaving investigators with an extensive crime scene to scour. No police officers were injured in the attack, the authorities said.

A little over two years ago, a young man was charged with attempted murder after he entered a mosque near Oslo armed and wearing body armor and a helmet. He was overpowered by a worshiper.

And in 2011, a lone political extremist bombed a government center and lay siege to an island summer camp for young members of the governing Labor Party, killing dozens of people.