Merry Christmas, gamers: 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 the group's role in all of this remains unconfirmed, it's worth noting that the group threatened last week to take down Xbox Live and PSN, according to Business Insider. And again, Lizard Squad has already proven it can successfully pull off such attacks, not to mention other malicious pranks.

Whatever the cause, 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 support 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.

"According to Vox.com, Lizard Squad brought down Sony’s PlayStation network with a similar attack in August, and Business Insider UK said the group took down PlayStation and Xbox at the beginning of December. It has claimed responsibility for disrupting other online gaming sites. The group also tweeted a bomb threat against a commercial flight carrying Sony Online Entertainment President John Smedley, forcing an emergency landing.

The group last week threatened to take down PlayStation and Xbox over Christmas, according to Business Insider UK"