Spanish police have detained three cyber activists allegedly associated with the cyber collective known as Anonymous.
Law enforcement officials also seized a server from one of the activists, which investigators believe was used to attack numerous websites, including the Sony Playstation Store, two Spanish banks, an Italian energy company, as well as the government domains of Egypt, Libya and Iran.
In addition, police identified software "designed specifically to infect" computers, as well as "evidence" of sophisticated encryption and other techniques for cloaking an individual's identity.
The three activists - thought to be senior members of Anonymous - are currently being held on suspicion of causing economic damage and breaching privacy laws.
"They are structured in independent cells and make thousands of simultaneous attacks using infected 'zombie' computers worldwide," Spanish police claimed in a statement obtained by Reuters.
"This is why NATO considers them a threat to the military alliance... They are even capable of collapsing a country's administrative structure."