Controversial whistle-blowing website WikiLeaks has been targeted by hackers this week.
The attacks come as the site continues to release thousands of previously unpublished US diplomatic cables, some still classified.
“WikiLeaks.org is presently under attack,” said a message on WikiLeaks’ Twitter page.
The site’s owners later described the problem as “a cyber attack.” In a subsequent message on its Twitter feed, it said the website was back up though some users were having problems accessing it.