Twitter has experienced a major outage, with users across the world affected.
The company said there had been problems with its “internal systems” and that there was no evidence of a security breach or hack.
Users in countries including the US and UK were unable to use the platform for more than an hour.
Some traffic has now been restored and the company said it was working to get the site “back up and running for everyone”.
According to DownDetector.com, reports of problems with Twitter began to spike at about 21:30 GMT.
The site said users from around the world – including Japan, Australia, Argentina and France – had reported being unable to use the platform.
In the US, there were tens of thousands of reports of problems.
Users were sent error messages including “something went wrong” and “Tweet failed: There’s something wrong. Please try again later.”
Internet monitoring group NetBlocks confirmed that the incident was “not related to country-level internet disruptions or filtering”.