Armed robbers stole paintings by Cezanne, Degas, van Gogh and Monet worth $163.2 million from a Zurich museum, police said, calling it a "spectacular art robbery." The robbery of the four paintings occurred Sunday at the E.G. Buehrle Collection, one of Europe's finest private museums for Impressionist and post-Impressionist art, police said.

Three masked men who entered the building with pistols are still at large. A police statement said the three robbers wearing ski masks and dark clothing entered the museum a half-hour before closing Sunday. While one of the men used a pistol to force museum personnel to the floor, the other two robbers went into the exhibition hall and collected the four masterpieces. They loaded the paintings into a white vehicle parked in front of the museum. Police, asking for witnesses to come forward, said it was possible that the paintings were partly sticking out of the trunk as the robbers made their getaway.

A reward of $91,000 was offered for information leading to the recovery of the paintings: Claude Monet's "Poppy Field at Vetheuil"; Edgar Degas' "Ludovic Lepic and His Daughter"; Vincent van Gogh's "Blooming Chestnut Branches"; and Paul Cezanne's "Boy in the Red Waistcoat." Sunday's theft came days after Swiss police reported that two Pablo Picasso paintings were stolen from an exhibition near Zurich. The two oil paintings, "Tete de cheval" ("Head of horse") and "Verre et pichet" ("Glass and pitcher"), were on loan from the Sprengel Museum in Hannover, Germany.

The FBI estimates the market for stolen art at $6 billion annually, and Interpol has about 30,000 pieces of stolen art in its database, while only a fraction of pieces are ever found.