The men aged 19 to 48 were seized Friday on a tip from the intelligence services that they were planning a terrorist attack shortly in the Netherlands. There was no immediate information on the intended target of the alleged attack.
European officials often step up security around the holidays, but this year especially after a Nigerian man last Christmas Day taped explosives to his underwear and allegedly tried to blow up a plane as it approached Detroit.
There also have been growing concerns in Europe about holiday season attacks following a suicide bombing in Sweden and attacks on two embassies this week in Rome.
Dutch police searched a call center, four houses and two motel rooms in the Rotterdam area, prosecutors said in a statement Saturday. No weapons or explosives were found.
Six of the suspects live in Rotterdam, five have no permanent residence and one man comes from Denmark, they said.
Last year, 24-year-old Umar Farouk Abdulmutallab, who had studied in London, boarded a Northwest Airlines flight to Detroit from Amsterdam. He is accused of trying to blow up the flight, and a judge in a federal court in Detroit has entered a not-guilty plea on his behalf.
On Thursday, anarchists sent mail bombs to the Rome embassies of Chile and Switzerland, injuring two mail employees at those embassies.
A top Italian security official said the attackers wanted to avenge blows by those countries against their movement.
Last Monday, 12 men were also arrested in Britain in the largest counterterrorism raid there in nearly two years. The men – whose ages range from 17 to 28 – were arrested in London, Cardiff, Stoke-on-Trent and Birmingham. At least five were of Bangladeshi origin.
Security officials said a large-scale terror attack was aimed at British landmarks and public spaces. Lord Carlile, the government’s independent watchdog for terror, said the alleged plot appeared significant and involved several British cities, but he did not identify the targets.
Police removed computers from the suspects’ homes. They have up to 28 days to either charge the men or release them.
Possible targets that were scouted include the Houses of Parliament in London and shopping areas around the U.K., according to a security official who spoke to The Associated Press on condition of anonymity because the investigation was ongoing.
French officials, meanwhile, have ordered plainclothes police patrols in key tourist sites for the holidays, including an extra 6,000 more police for New Year’s Eve.
Europe has been the target of numerous terror plots by Islamist militants. The deadliest was the 2004 Madrid train bombings, when shrapnel-filled bombs exploded, killing 191 people and wounding about 1,800. A year later, suicide bombers killed 52 rush-hour commuters in London aboard three subway trains and a bus.
In 2006, U.S. and British intelligence officials thwarted one of the largest terror plots yet, a plan to explode nearly a dozen trans-Atlantic airliners.