The Twitter micro-blogging and social networking service has been hit with a denial of service attack Thursday morning that has rendered the site unavailable for users.
Twitter reported the attack in a post on its blog and is continuing to deal with the problem.
"We are defending against this attack now and will continue to update our status blog as we continue to defend and later investigate," the company said.
In a status report about an hour following its acknowledgement of the attack, Twitter reported that the site was back up, but users still were having trouble reaching it.
(More to follow...)