The operators of the WikiLeaks Web site are in the midst of a game of virtual dodge ball, as they battle a diverse group of hackers and try to keep their stash of once confidential documents online.

The WikiLeaks site has been under attack since Sunday when it began releasing some of the more than 250,000 confidential State Department documents it has obtained. Someone portraying himself as an American patriot took credit for the first spate of disruptions to the site, a claim that security experts said was credible.

Later in the week, the organization faced more widespread attacks from armies of zombie computers in Europe, Russia and Asia that try to overwhelm Web sites with floods of requests. It is unclear who orchestrated these actions, security experts said.

WikiLeaks relies on a dispersed network of computer servers to keep its information available but sought extra computing muscle after facing so many attacks. So it turned to Amazon.com, which provides a variety of Web services to help fend off the hackers.