Sony

Sony has been hit by another hack -- the PlayStation Network and store has been targeted and taken offline.

Although the online store for games, films and TV shows seems to be back up and running once again, visitors to the site were brought to a halt on Sunday night with a message reading, "Page Not Found! It's not you. It's the Internet's fault." Gamers have also reported difficulties while trying to play online games.

Sony says only, "We are currently investigating the root cause for the issue."

An anonymous individual or group calling itself Lizard Squad has claimed responsibility with a tweet late on Sunday reading "PSN Login #offline #LizardSquad".

The latest hack comes less than a week after Sony celebrated the 20th birthday of the PlayStation games console. As well as building games consoles and selling games, Sony has a movie studio, which fell prey to hackers last month. The hackers claim to have stolen around 100 terabytes of internal Sony files and films in that attack.

The information included customer passwords, Sony employees' Social Security numbers, and contracts with celebrities. A number of forthcoming Sony movies including "Annie", "Mr. Turner" and "To Write Love On Her Arms" were also leaked.

Some had speculated that the North Korean government may have been motivated to hack Sony in retaliation for the forthcoming comedy film "The Interview," about a plot to assassinate the country's leader, Kim Jong-Un. The North Korean government on Sunday denied responsibility for the attack.

On Monday, the hacktivist group which claimed responsibility for the hack, "Guardians of Peace," issued a new threat on GitHub demanding Sony stop "immediately showing the movie of terrorism which can break the regional peace and cause the War!" The threat is an allusion to "The Interview," although they did not mention it by name. The group also leaked around 2.7 gigabytes of new files containing emails from Sony Pictures Entertainment co-chairman Amy Pascal and Sony Pictures Television president Stephen Mosko.

Update, December 8 at 2:35 p.m. PT: Adds details on the latest threat from Sony Pictures hackers.