Alerted by an alarm but arriving at the museum in Rotterdam after the thief or thieves had fled, police said they had launched a major investigation that includes interviewing possible witnesses and examining closed-circuit television.[break]
"On Tuesday morning seven artworks were stolen from the Kunsthal in Rotterdam," police said in a statement, adding the burglary took place at around 3:00 a.m.(0100 GMT).
The art theft is the biggest in the Netherlands in more than 20 years.
Museum director Emily Ansenk, who flew back to Rotterdam after hearing of the theft during a visit to Turkey, told a press conference that what had happened was "a nightmare for any museum".
The stolen paintings were "unique works that are known around the world," she said.
They are Pablo Picasso´s "Tete d´Arlequin", Henri Matisse´s "La Liseuse en Blanc et Jaune", Claude Monet´s "Waterloo Bridge, London" and "Charing Cross Bridge, London", Paul Gauguin´s "Femme Devant une Fenetre Ouverte, dite La Fiancee", Meyer de Haan´s "Autoportrait" and Lucian Freud´s "Woman with Eyes Closed".
After having initially declined to name the stolen paintings, the police said that after consulting with the owners, they can now release photographs of the works.
The chairman of the museum´s board, Willem van Hassel, told journalists that "technical security had been chosen deliberately which meant that nobody was at the museum but there was video."
He declined to discuss the value of the stolen works, but an expert at the Cornette de Saint-Cyr auction house in Paris who requested anonymity said the paintings were worth "between 150 and 200 million euros."
"A major investigation is under way and forensics are at the scene," Rotterdam police spokeswoman Patricia Wessels told AFP. "We´re investigating how they got access, what time it happened and who did it."
Dutch state television showed a police forensic team dusting one of the Kunsthal´s outer doors for fingerprints.
The NOS broadcaster said the haul was worth "millions and millions of euros (dollars)", but the paintings are so famous that it will be difficult to get anything like their real value on the black market.
It is the biggest art theft in The Netherlands since 20 paintings were stolen from Amsterdam´s Van Gogh museum in 1991.
"We´re a bit shocked that something like this happens here and at the same time we have some respect for thieves who got away with something likes this," said student Ibo Bose, disappointed not to be able to visit the museum.
"Police are interviewing possible witnesses and examining closed-circuit video footage," the police statement said. "An initial investigation suggests that the robbery was well prepared."
The police spokeswoman said that police were alerted during the night when an alarm went off but the thief or thieves had made off by the time police arrived at the scene.
Museum director Ansenk said police arrived at the scene just five minutes after the alarm went off in Rotterdam´s museum park where few people go at night.
The works were among the 150-strong Triton Foundation´s collection, which was being shown in its entirety to the public for the first time to mark the museum´s 20th anniversary, the Kunsthal´s website said.
The collection "has developed into one with an international reputation and which comprises representative works by the most important and influential artists of the late 19th century to the present day," it said.
The exhibition "comprises works from almost every significant art movement", it added.
The Kunsthal, which means "art hall", has no permanent collection of its own. It will reopen on Wednesday, the museum said.
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