Romanian police have arrested three people on suspicion of involvement in the spectacular theft last year of seven masterpieces, including Monets and a Picasso, from a Rotterdam museum, police said Tuesday.
Romanian police told AFP that they "led operations in connection with the theft of paintings in the Netherlands", but refused to elaborate.
Rotterdam police spokeswoman Yvette van den Heerik told AFP that three arrests had been made in connection with the October theft of the paintings, worth between 50 million and 200 million euros ($66 million and $266 million) on the open market, from the southwestern Dutch city's Kunsthal museum.
"Three suspects have been arrested in Romania in connection with the painting theft but no painting has been recovered," she said.
"They're still being detained and are being questioned about their possible role in the theft."
The three Romanians were detained for up to 29 days at the request of the Romanian prosecutor's office dealing with terrorism and organised crime (DIICOT), according to local news agency Mediafax.
When contacted by AFP, DIICOT spokeswoman Nadina Spinu confirmed only that an investigation was "ongoing" and declined to give further details so as "not to interfere" with the probe.
Seven masterpieces, including paintings by Pablo Picasso, Henri Matisse, Claude Monet and Paul Gauguin, were stolen from the Kunsthal museum on October 16, the biggest such heist in 20 years.
The Kunsthal museum declined to comment on the arrests when contacted by AFP.
Rotterdam police said in a statement that a wide-ranging investigation into the theft was ongoing, nationally and internationally, "including cooperation with the Romanian police".
"The three were arrested as part of a Romanian investigation and not at the request of Rotterdam police," the statement said.
The spectacular theft gripped the Netherlands and the art world as police apparently struggled to piece the crime together, despite putting 25 officers on the case.
Dutch police released grainy security camera footage of the theft, which took place around 3:00 am. The footage showed two apparently young males entering and leaving the museum in central Rotterdam within barely 90 seconds.
Police said they were releasing the images in the hope that witnesses might recognise the "odd" bags the thieves were carrying.
Investigators appealed to anyone who might have been in the area, including taxi drivers, hospital employees and nightclub-goers.
They also sought the help of anyone who might have taken photographs or video while visiting the museum in the weeks preceding the theft, in the hope that the thieves might have been caught casing the artworks.
Some experts speculated that the theft was linked to a massive drugs bust in Antwerp that left some criminals needing to pay off big debts quickly.
Experts said that any black-market sale would net just five to 10 percent of the paintings' real worth, if they can be sold at all, and that the figure would drop further still if the paintings were damaged in the theft.
Thieves in 1991 stole 20 works by Vincent van Gogh in Amsterdam, but they were dumped less than an hour later.