The European Commission and the External Action Service have been hit by a "major" cyber attack ahead of an EU summit on countries' economic strategies and the war in Libya. Officials are comparing it to an assault on the French finance ministry last year ahead of a G20 meeting.

The EU's joint policy body, Europol, is angling to host a new European cyber crime centre, with the European Commission due next year to decide where to put its new defence against online threats.

EU and US cyber experts on Thursday sat together and brainstormed on how they would deal with attacks aimed at extracting government secrets or taking control of nuclear plants.

Faced with increasing cyber attacks, the EU is looking at a new law criminalising the use of 'zombie' computers and is setting up a 'cyber crime' agency and special teams of IT firefighters. But specialists and data privacy defenders remain unconvinced.

With the discovery of Stuxnet, a computer worm believed to have been developed by the US government to shut down a nuclear plant in Iran, European companies like Siemens are coming under increased pressure to secure software operating 'critical infrastructure' such as power plants or water treatment facilities.

European companies selling online surveillance technology have come under increasing criticism from NGOs and the European Parliament after it emerged their products had helped regimes in Iran, Egypt and Libya to clamp down on protesters.