In a statement, police say they arrested the three "leaders" of the collective in Spain at locations in Barcelona, Valencia and Almeria.

They are accused of using a server set up in one of the member's house to participate in the recent attack on Sony's Playstation Network as well as the Web sites belonging to BBVA and Bankia.

Italian energy group Enel and sites for governments in Egypt, Algeria, Lybia, Iran, Chile, Colombia and New Zealand were also hit.

The arrests are the first related to Anonymous in Spain and follow similar operations in the US and UK.

Anyonymous came to prominence last year after attacking financial services firms such as Bank of America, Visa, MasterCard and PayPal who refused to process payments for whistle-blowing Web site WikiLeaks.