Facebook, WhatsApp and Instagram, social media services, appear to be recovering after an outage that lasted as at the time of filing this report.
All three services are owned by Facebook and could not be accessed over the web or on smartphone apps.
Downdetector, which tracks outages, logged tens of thousands of outage reports for all three platforms around the world.
The last time Facebook had a disruption of this magnitude was in 2019.
During the outage, Mike Schroepfer, Facebook’s chief technology officer tweeted his “sincere apologies” to those affected.
Some people also reported problems using Facebook’s virtual reality headset platform, Oculus, and apps which require Facebook logins were affected, including Pokémon Go.
An outage of this scale for such a long time is rare. The disruption in 2019 left Facebook and its other apps mostly inaccessible across the world for more than 14 hours.
As yet there has been no official reason given for the problem. But online network experts speculated it may involve an error with DNS, or the domain name system, for Facebook sites.
DNS is often compared to an address book or phone book for the internet, pointing web browsers to the computer system which serves the website they are looking for.
Previous issues with DNS led to widespread outages of several major sites earlier this year.
In one of those instances, it emerged that the blackout was caused by a single customer of a widely-used service who changed their settings, triggering a software bug affecting a huge number of websites.
Several other tech companies, including Reddit and Twitter, poked fun at the social media giant’s predicament – prompting responses from the affected apps.