The New York Times is the only major US newspaper included in the ban [GALLO/GETTY]

The US Air Force has blocked access for computers on its network to at least 25 websites that published sensitive diplomatic documents released by the Internet site WikiLeaks, a spokeswoman said.

Major Toni Tones, a spokesperson at Air Force Space Command in Colorado, said on Tuesday that the websites that carried WikiLeaks documents had been blocked and could not be viewed by any Air Force computer.

The Air Force "routinely blocks Air Force network access to websites hosting inappropriate materials or malware (malicious software) and this includes any website that hosts classified materials and those that are released by WikiLeaks," Tones said.

She said the action was taken by the 24th Air Force, which is commanded by Major Generral Richard Webber and is responsible for cyber warfare 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.

'Unfortunate'

"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 US newspaper included in the ban.

The newspaper's spokesman Robert Christie said in a statement that "it is unfortunate that the US Air Force has chosen not to allow its personnel access to information that virtually everyone else in the world can access."

Others media sites include Der Spiegel in Germany, the Guardian in Britain and Le Monde in France.

WikiLeaks released more than a quarter-million sensitive State Department cables in late November, revealing blunt, sometimes derisive depictions of foreign governments and leaders, which embarrassed Washington.

The White House formally reminded all federal employees and government contractors on December 3 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 US government would enforce this, but the White House said employees who inadvertently viewed the information should contact their US security offices at work.