Merry Christmas, game fans: Both Xbox Live and PlayStation Network are down this morning, apparently due to a denial-of-service attack. The notorious hacking group Lizard Squad -- which already carried out earlier attacks on Microsoft and Sony -- has claimed responsibility on Twitter for these latest outages. While Lizard Squad's role in all of this remains unconfirmed, the group did threaten last week to take down Xbox Live and PSN, according to Business Insider.

Regardless of who's behind this, the timing is obviously terrible: Plenty of people surely received one of the two consoles as Christmas presents today, while many more gamers would have happily spent the afternoon in front of the TV. In the meantime, both Sony and Microsoft have acknowledged the problem, with Sony issuing a tweet and Microsoft posting a message on its website: "We're working to address this as quickly as we possibly can," reads its status website. "Thanks for your patience, Xbox members." In an email, a Microsoft spokesperson declined to comment further or say when the company expects to restore service. We've also asked Sony to comment and will update this post if and when it does.