Twitter crashed this afternoon leaving millions unable to communicate via the firm’s web site.
The San Francisco firm confirmed the technical problems on its web site status page.
It said: ‘Users may be experiencing issues accessing Twitter.
‘Our engineers are currently working to resolve the issue.’ The problems are a major embarrassment for the firm just a day before the Olympic opening ceremony.
The firm has been working closely with organisers to ensure the site is available.
In previous years, the site became notorious for its ‘fail whale’, the logo displayed when its service crashed or became overloaded.
The site has already been widely used by athletes and fans alike – and has led to one athlete being kicked out.
A Greek triple jumper was yesterday expelled from the Olympics after she posted a racist joke on Twitter.
Voula Papachristou was kicked out of her national team for mocking African migrants and expressing support for a far-Right political party.
Her offending message – which was referring to reports of mosquitoes carrying the West Nile virus in her home country – read: ‘With so many Africans in Greece, at least the West Nile mosquitoes will eat home made food!’
The problems came just hours after Google’s Talk messaging system faced a massive outage worldwide.
After users facing the problem took to Twitter, Google admitted the problem on its official Google Talk app status page.
‘We’re aware of a problem with Google Talk affecting a majority of users,’ it said.
‘The affected users are able to access Google Talk, but are seeing error messages and/or other unexpected behavior’