STOCKHOLM Four people suspected of involvement in the theft of a Rembrandt and two works by Renoir from Sweden's Top Museum at the end of December were arrested and charged on Thursday, police said.

According to an AFP report, the four, who have not been named, were arrested early Thursday after police carried out extensive searches in the Stockholm area.

The group are thought to be behind the plot to snatch a self-portrait by Dutch master Rembrandt and two works by French impressionist Pierre-Auguste Renoir, valued at up to 30 million dollars (31.9 million euros), from Sweden's National Museum on December 22.

The four suspects, all of Swedish nationality, have been jailed and charged by the state prosecutor. Police did not reveal the specific charges against those taken into custody.

The arrests come three days after the thieves tried to claim several million kronor in return for handing over the haul. The police, who were given photographs of the works to prove their authenticity, refused to surrender the ransom.

"We don't intend to hand over even one crown," Leif Jennekvist, in charge of the investigation, told journalists, saying such a move could encourage others to lift works of art.

The three pieces are still missing and police said they did not know if the paintings were still in Sweden, or if they had been whisked abroad, as many experts have suggested.

Other arrests are expected in connection with the December raid and police were planning additional searches for Thursday night, Jennekvist said.

Three men armed with pistols and a shotgun entered the Central Stockholm Museum as it was closing on December 22, removed the paintings from display and promptly fled as numerous witnesses looked on.

The prestigious paintings, each valued at between 7.5 and 10 million dollars, were uninsured.

The gunmen escaped on a small boat moored near the museum, speeding off into the darkness. Police combed the city in boats, cars and on foot but searches yielded no leads and no suspects.

The raid was one of the most daring art thefts in the country's history, but not the most costly.

In 1993, thieves made off with a haul of paintings including works by Pablo Picasso and Georges Braque in a stash worth an estimated 50 million dollars. Some of the works were never recovered.

The National Museum houses some of the most prestigious collections of painting, sculpture and drawing in Sweden. Other artists whose work is on display there include Rubens, Goya, Degas and Gauguin.