Twitter went down this afternoon for at least tens of thousands of users around the world.
After about half an hour, the social network appeared to be returning for some users.
Thousands of people in the UK and the United States complained to the web monitoring service Down Detector.
There had been 29,266 complaints by 1.30pm UK time, and 54,994 in the United States.
Users in other countries, including Mexico, Brazil and Italy also reported issues.
When loading the site, the page displayed an error sign and asked users to try again.
Most reported problems were to do with accessing the Twitter app and website.
Twitter's own status page offered no information during the outage, showing the message "All Systems Operational."
Soon after it began to return.
This is the first major Twitter outage since problems in the US in February due to a technical bug.
On October 4, 2021, Facebook, Instagram and Whatsapp became unavailable for a period of six to seven hours.
The outage was caused by the loss of IP routes to the Facebook servers.
The Tesla CEO had reached a deal to buy Twitter in April, but began to voice doubts following allegations of spam accounts.