The arrests come as the Spanish government announced heightened security measures would be in place over the Christmas and New Year holidays.
Hundreds of police officers took part in the overnight operation to arrest the suspects at two locations in the Barcelona area.
The three are reportedly being transferred to Madrid to face questioning on Monday.
A police statement said the suspects had “started negotiations to procure explosives”, and added that foreign intelligence agencies were also involved in the investigation.
It said the three had “established contact with an intermediary in central Europe” said to be in a position to supply explosives.
The three were named as Majid Bakkali, Mohamed Douha and Abdelkader Farhaoui.
Police searched their homes and are now examining documents and computer material seized from their apartments.
Police also detained three others for questioning, however these are not suspected of being linked to international terrorism.
The arrests come just hours after Prime Minister Jose Luis Rodriguez Zapatero announced a special security plan to prevent any terrorism attacks would be activated, including increasing police and security on public transport, in shopping areas and around tourist sites.
Meanwhile, a parliamentary inquiry into the March 11 coordinated bombings of Madrid trains completes its examination of witnesses.
The inquiry’s president said it will now draw up its conclusions, and the committee has made an in principle decision.
Both Prime Minister Zapatero and his predecessor, Jose Maria Aznar, have appeared before the inquiry, with Mr Zapatero accusing Mr Aznar of misleading Spanish people by trying to pin the blame for the blasts on Basque separatists.
While the commission is not expected to publish its report before the first anniversary of the attacks, it should be able to present preliminary conclusions before that date.
More than 120 suspected Islamic extremists have been arrested in Spain since the March 11 attacks, in which 191 people were killed and 1,900 were injured.Categories : 上海性息网