Facebook and Instagram were reported to be down for users around the world on Thursday night.
The outage began shortly before 10.30pm UK time — 5.30pm ET in the United States — according to website DownDetector and appeared to be affecting all users of both platforms.
There was no update via Twitter from Facebook, which runs both platforms.
Users reported that they were unable to load images or create or upload posts.
There was no indication of when service might be restored.
Users said the Facebook Messenger app was also not working.