STOCKHOLM, Sweden (AP) _ Police searched for clues Saturday to find robbers who made off with three valuable paintings by Rembrandt and Renoir from the National Museum the evening before.

A man walked into the waterfront museum five minutes before closing time Friday night, pointed a submachine gun at an unarmed guard and stood watch while two accomplices already inside snatched the paintings off walls.

The robbers sped away in a boat moored near the museum. Police found the boat, but not the thieves or the paintings, which museum officials say are worth several million dollars.

``We're working with witness accounts and technical evidence, but there is no lead pointing to any certain direction,'' police spokesman Bjoern Pihlblad said. ``We're still dependent on getting information from ... anyone who might have seen anything.''

The robbers spoke Swedish, he said, and police were presuming they were still in the country. The international police agency Interpol was notified anyway, he said.

About the paintings, he added, ``In these cases it's normal that the ... robbers stash them away for a while.''

The paintings are:

_ a self-portrait by Rembrandt, about eight by 12 inches including the frame, painted on golden-surfaced copper plate to give a special light to the face. It was painted in 1630 and bought by the museum from a private collection in 1956.

_ ``Conversation,'' by Renoir, a 14-by-18-inch close-up of a man and a woman with her back turned to the viewer, acquired by the museum in 1918.

_ ``Young Parisian,'' by Renoir, a young girl, acquired by the museum in 1913.

Like other government property, the paintings were not insured.

``It's a great loss to the museum,'' acting museum director Torsten Gunnarsson said.

The National Museum's collections contain about 15,000 paintings and sculptures. One of the most valuable paintings is Rembrandt's ``Kitchenmaid.''

The biggest art theft in Sweden happened at Stockholm's Modern Museum in November 1993 when works by Picasso and Georges Braque worth about $48 million were stolen.

Art experts and police said it will be hard to sell the paintings because buyers and auction houses will either know, or demand proof of, the paintings' origins.

``Either someone ordered these paintings, some millionaire who wants to peek at them in his safe, or the thieves will try and blackmail the museum'' by demanding a ransom for their safe return, Pihlblad said.