Facebook users worldwide complained on Saturday (Aug 26) after technical issues left them unable to access or use the site properly.
DownDetector, a UK site that collects reports of website crashes, said the issues started around the early afternoon (9.15pm, Singapore time). At its peak, more than 1,800 people said they were experiencing problems on the website.
Many users reported a "total blackout", while others only experienced issues with some features - including logging in to both the website and its mobile app, sending messages and posting status updates.
Some Facebook users said they saw messages telling them that the site is undergoing "required maintenance".
Users on photo-sharing app Instagram - owned by Facebook - also experienced problems at around the same time.
Some users took to rival social network Twitter to complain about the outage and poke fun at the situation.
The issues appeared to have been resolved for many users after an hour.