Spanish police have arrested three people they identified as national “leaders” of the online “hacktivist" group Anonymous.
The three were arrested in the first action of its kind in Spain on charges of computer crime involving companies including Sony and Spanish banks BBVA and Bankia.
A 31-year-old man was arrested in Gijón, in northern Spain, where police found a server they believed was involved in distributed denial-of-service (DDoS) attacks on websites.
The other two detainess, identified as network administrators involved in the attacks, were arrested in Barcelona and Alicante.
Spanish police believe the Anonymous group has also hacked government websites in Egypt, Algeria, Lybia, Iran, Chile, Colombia and New Zealand.
Anonymous members are known for wearing Guy Fawkes masks in public, and for using a symbol of a headless suited man in online communications.
The group often relies on the simultaneous actions of large numbers of computer users to overwhelm websites which they are ideologically opposed to.
The Fine Gael website was the subject of a cyberattack claimed by someone purporting to be from Anonymous last January.
"They are structured in independent cells and make thousands of simultaneous attacks using infected 'zombie' computers worldwide. This is why Nato considers them a threat to the military alliance," Spanish police said. "They are even capable of collapsing a country's administrative structure."
This case is the first of its kind in Spain, although the US and UK have arrested several people on similar charges in the past.