Hackers claim to have downed Sony's PlayStation Network, as the company's cyber-attack troubles continue. Hacking group Lizard Squad are taking credit for the latest attack on Sony's network, which is preventing players from logging in to the online gaming network and has taken down the PlayStation Store.

Sony has acknowledged the problem, posting a message on the PlayStation Twitter account that says it's working to restore the service.

The PlayStation Store is also down. At the time of publication, the website was simply displaying a "Page Not Found" warning, with the message: "It's not you. It's the Internet's fault."

The attack on the PlayStation Network follows a torrid week of hacking troubles for Sony. Last week, the firm's movie studio was hacked, resulting in the leak of unreleased films and other confidential data, such as staff salaries and the amount actors were paid to appear in the company's movies. The salary paid to Princess Beatrice in her first year of working for the company's production department was also unveiled.

It was first suggested that North Korea may have been behind the attack on Sony's network, taking revenge for a forthcoming Sony movie which centres on a plot to assassinate the country's leader, Kim Jong Un. The North Korean government finally denied responsibility at the weekend, but described the hack as a "righteous deed" that may have been carried out by the country's "supporters and sympathisers".

It's fairly unlikely the Lizard Squad are North Korean sympathisers, but more interested in gaining notoriety. The collective last week claimed the credit for a denial-of-service attack on Microsoft's Xbox Live network, which resulted in some users being able to access the service. The group's Twitter account warned of more trouble to come over the weekend. "Unlike Santa, we don't like giving all of our Christmas presents out on one day," read a message posted on the Lizard Squad Twitter account . "This entire month will be entertaining."

The hacking group posted a message claiming to have a "new leader", identified as @GDKJordie , who in messages posted on his own account, claims to have funded the group's activities through the sale of cannabis.

It's not the first time Sony's PSN has been downed by hackers. In 2011, the service was down for five days as the result of an attack which saw the personal data of up to 70 million account holders compromised.