Millions of social media enthusiasts were left in a state of panic this morning after an alleged cyber attack cased Facebook and Instagram to shut down worldwide for around an hour.
The online group Lizard Squad have claimed responsibility for the hack, which took the two sites down at around 6am British time.
Both sites, which have a total of 1.5billion users, appeared with error messages in the United States, Europe and Asia for around an hour.
But despite hackers claiming they took the social media giants offline, Mark Zuckerberg's Facebook, which also owns Instagram, refused to say what the fault was.
There were claims online that the super-snowstorm that is over America's east coast may have knocked out its servers.
The social media blackout also affected the dating mobile app Tinder, as well as AOL Instant Messenger and Hipchat.
Facebook in the UK and Ireland said it was "aware that many people are currently having trouble accessing Facebook and Instagram".
"We're working to get things back to normal as quickly as possible," a spokeswoman said.
An Instagram spokesman posted on Twitter: "We're aware of an outage affecting Instagram and are working on a fix. Thank you for your patience."
The hashtag #facebookdown and #socialmeltdown2015 immediately started tending on Twitter, which remained operational.
A group of hackers known as the Lizard Squad seems to be taking credit for the attacks.
Around the time the sites went down the group tweeted "Facebook, Instagram, Tinder, AIM, Hipchat #offline #LizardSquad'.
Facebook, Instagram, Tinder, AIM, Hipchat #offline#LizardSquad
— Lizard Squad (@LizardMafia) January 27, 2015
Lizard Squad has caused havoc in the online world before, taking credit for attacks that took down the Sony PlayStation Network and Microsoft's Xbox Live network last month.
Yesterday, it claimed to have targeted The Malaysia Airlines website, leaving a message saying "404 Plane Not Found" and declaring it part of their "cyber caliphate".
In August, it also tweeted to American Airlines that there might be explosives on a plane carrying the president of Sony Online Entertainment, which makes video games, forcing the flight to be diverted.
