Twitter said on Tuesday its social network was suffering outages in some parts of the world and it was working to resolve the issues, which appear to be concentrated in Europe, according to external monitoring sources.
Both Twitter web and mobile services were suffering outages, with smartphone users receiving the warning: "Tweets aren't loading right now."
"Some users are currently experiencing problems accessing Twitter," a statement on the company's Twitter status site reads (status.twitter.com/).
"We are aware of the issue and are working towards a resolution."
A company spokeswoman had no further comment.
Outages were reported across northern Europe and appear to be concentrated in Britain, France and Germany, according to DownDetector.uk, an independent Twitter outage monitoring service.