Italian cyber-security firm Hacking Team blames foreign government for attack on its systems

Unknown hackers last week downloaded 400GB of data from the firm, which makes surveillance software that allows law enforcement and intelligence agencies to tap into the phones and computers of suspects.

Much of the data, including thousands of private corporate emails, has since been dumped onto the Wikileaks website. The source code of a number of its top secret programs has also been published online.

"Given its complexity, I think that the attack must have been carried out at a government level, or by someone who has huge funds at their disposal," David Vincenzetti, the CEO of Hacking Team, told Sunday's La Stampa newspaper.

He did not speculate on who it might have been.

The company has advised clients to halt their use of its programs until they can upgrade the compromised software, but warned that all computer systems might now be vulnerable.

"Hacking Team's investigation has determined that sufficient code was released to permit anyone to deploy the software against any target of their choice," the company said in a statement on its Internet site.