Wikileaks documents reveal sensitive US cables: Report

US state department documents released by whistle-blowing website WikiLeaks provided candid views of foreign leaders and sensitive information on terrorism and nuclear proliferation, the New York Times reported on Sunday.

The documents show Saudi donors remain chief financiers of militant groups like al-Qaeda and that Chinese government operatives have waged a coordinated campaign of computer sabotage targeting the United States and its allies, according to a review of the WikiLeaks documents published in the Times.

The WikiLeaks documents also show US defence secretary Robert Gates believes any military strike on Iran would only delay its pursuit of a nuclear weapon by one to three years, the Times reported on its website on Sunday.

The Pentagon immediately condemned WikiLeaks' "reckless" dump of classified state department documents and said it was taking steps to bolster security of US military networks.

"The (defence) department has undertaken a series of actions to prevent such incidents from occurring in the future," Pentagon spokesperson Bryan Whitman said.

The White House said the leak of the diplomatic cables could compromise private discussions with foreign governments and opposition leaders and may put at risk the lives of named individuals living "under oppressive regimes."

The pending documents release had been widely reported for more than a week and expected on Sunday.

The US government, which was informed in advance of the contents, has contacted governments around the world, including in Russia, Europe and the Middle East, to try to limit any damage. Sources familiar with the documents say they include corruption allegations against foreign leaders and governments.

WikiLeaks had reported earlier on Sunday that its website was under attack, but said later that media outlets would publish some of the classified documents it had released even if the group's website crashed.

"El Pais, Le Monde, Speigel, Guardian & NYT will publish many US embassy cables tonight, even if WikiLeaks goes down," the website said in a Twitter posting an hour after it tweeted that its site was under attack.

The state department had warned WikiLeaks that the expected release would endanger countless lives, jeopardise American military operations and hurt international cooperation on global security issues.

The department's top lawyer urged WikiLeaks founder Julian Assange in a letter on Saturday to keep classified documents off the website, remove records of them from its database and return any material to the US government.