Electronics giant Sony are warning users of its PlayStation Network to be on the lookout for fraudulent activity amid fears their data has been hacked.
The warning follows what Sony describes as 'an illegal and unauthorised intrusion' into its systems which may have allowed access to the personal information of an estimated 70m gamers worldwide.
A statement released by Patrick Seybold, Senior Director of Corporate Communications & Social Media at Sony, said: "While there is no evidence at this time that credit card data was taken, we cannot rule out the possibility."
Since the attack, thought to have occurred between April 17 and April 19, Sony has taken its online gaming, music, movies, sports and TV services offline.
Questions will now be asked how a company as large as Sony became the victim of hackers and what can be done to protect against future intrusions.
The company has now called in the help of an outside security firm to address these concerns.
In a statement on their website Anonymous said: "While it could be the case that other Anons have acted by themselves, AnonOps was not related to this incident and takes no responsibility for it."
The statement also accuses Sony of taking advantage of the group's previous animosity to explain an internal problem with company servers.
Anonymous' previous Operation Sony campaign was intended to be a retribution for the company's impending legal action against hacker George Hotz.
Of the most recent attack, Mr Hotz said: "The fault lies with the executives who declared a war on hackers, laughed at the idea of people penetrating the fortress that once was Sony, whined incessantly about piracy, and kept hiring more lawyers when they really needed to hire good security experts."
Sony now plans to reintroduce its online services incrementally with gaming due back online during the first week of May, with other services returning to normal by the middle of the month.