Police in Spain have arrested three suspected members of an internet hacking group known as Anonymous.
Those detained are facing charges of cyber attacks against targets that include governments, businesses and banks.
Anonymous has previously claimed responsibility for attacks on Sony and coordinated action in defence of WikiLeaks.
High tech crime unit chief Manuel Vazquez said Anonymous hackers pose great threats to international security.
''In a recent brief, NATO said it considers Anonymous, like Al Quaeda, the Taliban and North Korea an important threat to the organisation because they could get sensitive data and disclose it,'' he said.
