California: Facebook and Instagram are down for thousands of users around the world.
Those attempting to go onto the sites are being shown a blank page, with nothing loading.
Some have reported they can only load certain parts of the social media giants’ websites or apps.
Other reports suggest the sites work fine until they try to post something, at which point it shuts down.
The issue appears to be widespread, with reports of outage popping up in Brazil, Japan, India and parts of Europe – though the outage has not affected everyone in these regions.
It remains unclear what is causing the issues for now, and Facebook is yet to confirm its technical difficulty on its official status page.
Users have gone to sites like DownDetector and Outage Report to log that the social media giants are experiencing server downtime. The problems on both services began at around 4pm BST (11am ET).