A company spokesman said the problems occurred when Facebook was running traffic optimization tests to determine which data centers to route certain users to. He said the problems were not caused by a hacker, despite claims from a Twitter user with the handle @AnonymousOwn3r
The outages occurred midday Pacific Standard Time, and Facebook says it is now up and running properly.
Here's Facebook's statement:
Earlier today we made a change to DNS as part of a traffic optimization test, and that change resulted in some users being temporarily misrouted. We detected and resolved the issue immediately, but a small number of users located primarily in Western Europe experienced issues accessing the site while the DNS addresses repopulated. We are now back to 100 percent, and we apologize for any inconvenience.
Though the company didn't say which countries were hit, people talking about the problems on Twitter mentioned Sweden, Denmark, Ireland, Norway, and Portugal.