Police have recovered three pictures by Norwegian artist Edvard Munch in a raid a day after they were stolen from a hotel.
However, his iconic work The Screamtaken in a separate theft last year was still missing.
"Several people have been arrested ... some are Norwegian and others have a foreign background," Oslo assistant police chief Iver Stensrud said after a police raid in the Oslo area tonight.
He said police had recovered a 1915 Munch watercolour, Blue Dress, and two lithographs - a self-portrait and a portrait of Swedish playwright and novelist August Strindberg. It was unclear if they had been damaged.
Mr Stensrud said that it was impossible to say if the thieves were linked to those who stole The Scream, showing a terrified waif-like figure under a blood-red sky, and Madonnafrom Oslo's Munch Museum in front of dozens of tourists last August. But he reiterated police were confident of solving that theft too.
Hotel owner Widar Salbuvik said yesterday's robbers seemed amateurish. The stolen pictures were not even among the most valuable in the collection of 400 works ranging from Munch to Andy Warhol, he said.
Armed with a crowbar, two men broke into the country hotel south of Oslo and tore the three works off the walls and ran off after a worker in the Refsnes Gods hotel surprised them. Blue Dress, depicting a blonde woman, had been hanging in the hotel restaurant, which had just shut.
Art experts said the works snatched yesterday were minor compared to the 1893 The Screamand Madonna.
Experts have estimated The Screammight be worth €60 million if it could be sold legally at auction while Madonna, showing a raven-haired woman, might fetch €12 million.
Police do not know the fate of the stolen The Scream. Theories include that the theft was ordered by a shadowy foreign collector, that the robbers aim to demand ransom from the government or simply that a Norwegian crime gang wanted to show off its power with the brazen daylight robbery.
Munch, a Norwegian, developed an emotionally charged painting style that was of great importance in the birth of the 20th-century Expressionist movement. He died in 1944 at the age of 80.
In 1994, another version of
The Scream
was stolen from the National Gallery in Oslo and was recovered a few months later in a sting operation. Knut Forsberg, managing director of Blomqvist art auctioneers in Oslo, estimated that
Blue Dress
was worth perhaps €140,000, the Munch self-portrait about €50,000 crowns and the portrait of Strindberg up to about €30,000.