Facebook has denied that hackers took down its website this morning.
Hundreds of millions of people trying to access their Facebook profiles and accounts on Tinder and Instagram were locked out between 6.20am (GMT) and 7.10am.
Some media reports initially suggested hacker collective Lizard Squad was responsible for the outage, following a tweet from the group.
Facebook, Instagram, Tinder, AIM, Hipchat #offline #LizardSquadLizard Squad (@LizardMafia) January 27, 2015
However, Facebook said the problem was actually caused by an update that resulted in a server outage.
A spokesman said: "Earlier today many people had trouble accessing Facebook and Instagram. This was not the result of a third party attack but instead occurred after we introduced a change that affected our configuration systems.
"We moved quickly to fix the problem, and both services are back to 100 per cent for everyone."
The outage was severe enough to affect apps that rely on Facebook for their log-ins, and those trying to access Instagram were met with a "can't refresh feed" message.
Security specialist Mark James at antivirus company ESET said that Facebook is an attractive but unrealistic target for hackers.
"As great as the prize would be I doubt Lizard Squad or any of the other mainstream teams would be able to take down Facebook directly," he said.
"A few have tried and stated that they will but I think it's highly unlikely they will succeed. Both Facebook and Instagram rely on massive amounts of web traffic so the likelihood of a distributed denial of service (DDoS) succeeding would be slim."
