WikiLeaks claims it has come under a "mass" cyber attack just moments after it leaked 250,000 US embassy documents to media outlets across the globe.
"We are currently under a mass distributed denial of service attack," the group posted on its Twitter page on Sunday night.
Papers reported to have received the documents included Spain's El Pais, France's Le Monde, Germany's Der Speigel, the UK's Guardian, and The New York Times.
According to a report by The Guardian, the cables detailed Washington's fears over Pakistan's nuclear weapons program, speculation about Russian government links to crime gangs, harsh criticisms of the UK's Afghanistan war efforts and alleged "inappropriate behaviour" by a member of the British royal family.
The idea of launching a sustained cyber attack on the web site had previously been flagged in the United States.
A Washington Times editorial published after WikiLeaks' prior Afghanistan leak suggested that such an attack would solve the WikiLeaks problem, while a Fox News columnist wanted the US government to launch an "electronic assault" on the site and its ISP to prevent it from further releases.
Security researcher Mikko Hyponnen noted on his Twitter feed at 6:50am this morning (Sydney time) that the Wikileaks site had been down for several hours after the release of the documents, but had resurfaced at an IP address that he believed was hosted at Amazon's EC2.
"So it's in the U.S.A.," he noted.