Twitter experienced a major site outage on Thursday, with millions of users reportedly locked out of their accounts.
The service was reported as down on various websites.
Twitter confirmed the outage on its website.
It said:
Users may be experiencing issues accessing Twitter. Our engineers are currently working to resolve the issue.
The outage occurred on the same day that Google Chat suffered an outage for "a majority of users".
Social media addicts flocked to rival services including Facebook and Google Plus to report the outage.
"Twitter is down and I can't tweet about it. Internally, I'm a mess," said one user, Andy Bray, via Google's social network. "Need to keep composed, need to keep composed..."
Another user said: "Twitter is down. Let's go running and screaming around the office."
Twitter last experienced an outage of this scale in June.
More to follow.