An online service outage has affected Sony's PlayStation and Microsoft's Xbox game consoles.
The disruption disappointed gamers on Christmas Day. Xbox Live is now reported to be up and running, while Playstation Network remains offline.
Responsibility for the attack was claimed by a group called Lizard Squad, while another group, calling itself Finest Squad, said it was trying to get the games back online.
"I have the nation on strings," Lizard Squad wrote on its Twitter site. The group flooded Xbox and PlayStation servers with sustained requests - constituting or Denial of Service (DDoS) attack.
"Xbox and PSN have been restored. Give it about 30min to an hour for full service", Finest Squad claimed.
But frustrated users took to Twitter to vent their disappointment and anger at Lizard Squad, which also claimed responsibility for attacks on the PlayStation Network and Xbox Live earlier this month.
"Is Microsoft going to reimburse us for the live time that were missing out on that most of us paid for .. #xboxlivedown #Microsoft," wrote one user.
"PSN has been down for the past 48 Hours, my kids can't enjoy their Christmas present.#ChristmasRuined," wrote another.
Neither Sony nor Microsoft have confirmed the attack. But PlayStation and Xbox confirmed the outages of their networks, adding that they were working to restore the service.
Our engineers are continuing to work hard to resolve the network issues users have experienced today. Thanks for your continued patience!
— Ask PlayStation (@AskPlayStation) December 26, 2014
Some Xbox One users may currently be experiencing issues signing into Xbox Live. Please see http://t.co/99xfLNN0o8 for more info. ^AD
— Xbox Support (1-5) (@XboxSupport) December 26, 2014
The outage meant gamers were unable to play online and also impacted online components of hugely popular games such as Call of Duty, Madden, FIFA and The Sims 4.
Three Xbox platforms were affected by the service problem: Xbox One, Xbox 360 and Xbox on other devices, Microsoft's status website said.
Lizard Squad had issued a threat at the start of December and describes itself as the "Grinch of Christmas".
It is not clear what Lizard Squad wants or who they are, but some reports suggest the group could be Russian, though this has not been proven. A link on their Twitter site was originally a Russian-based domain.
The latest trouble for Sony comes after hackers calling themselves the Guardians of Peace broke into the company's internal systems and stole large amounts of data last month.
Originally posted at 10.20am
