Air Force Maj. Toni Tones said more than 25 websites have been blocked and cannot be viewed by any Air Force computer. The ban aimed at preventing the viewing of classified information does not apply to personal computers.
She said the action was taken by the 24th Air Force, which is commanded by Maj. Gen. Richard Webber and is responsible for cyberwarfare and computer security for the service. The move was approved by Air Force lawyers, she said.
The Army and Navy say they have not taken similar actions.
"If a site has republished the documents, then we block it," she said, adding that the move to prevent access to the media sites was done recently. She said she was not sure of the date.
Tones said the New York Times is the only major U.S. newspaper included in the ban. Others include Der Spiegel in Germany, the Guardian in Britain and Le Monde in France.
Tones said that the 24th Air Force routinely blocks network access to websites that host inappropriate material, including classified information such as that released by WikiLeaks. Any computer on the Air Force network is now unable to link to the sites.
WikiLeaks released more than a quarter million sensitive State Department cables in late November.
The White House on Dec. 3 formally reminded all federal employees and government contractors that anyone without a security clearance is not permitted to read classified documents, such as the diplomatic messages published by WikiLeaks, even on a personal computer at home outside work hours.
It was not immediately clear how the U.S. government would enforce this, but the White House said employees who inadvertently viewed the information should contact their U.S. security offices at work. The notice by the White House Office of Management and Budget said publication of the files by WikiLeaks "has resulted in damage to our national security."
The New York Times Co. issued a statement in response to the action Tuesday, saying "it is unfortunate that the U.S. Air Force has chosen not to allow its personnel access to information that virtually everyone else in the world can access."