|The whistle-blowing website run by Julian Assange, pictured, is set to make public its largest tranche of files [EPA]
US allies around the world have been briefed by American diplomats about the expected release of three million potentially embarrasing classified files by the WikiLeaks whistleblowing website.
"Across the state department, senior officials are reaching out to countries and warning them about a possible release of documents," PJ Crowley, the US state department spokesman, said.
He said that Hillary Clinton, the US secretary of state, had reached out to leaders in China, Germany, Saudi Arabia, the United Arab Emirates, Britain, France and Afghanistan regarding WikiLeaks.
"We are all bracing for what may be coming and condemn WikiLeaks for the release of classified material," Crowley said. "It will place lives and interests at risk. It is irresponsible."
The documents, believed to consist largely of diplomatic cables between overseas missions and the state department in Washington, were expected to be released over the weekend, although WikiLeaks has not confirmed the timing.
Steve Field, the UK prime minister's spokesman, had already confirmed that the government had been told of "the likely content of these leaks" by Louis Susman, the US ambassador to London.
Italy's foreign minister, Franco Frattini, also said that he had spoken with the US state department, which told him that there would be documents regarding Italy in the leak, "but the content can't be anticipated."
"We're talking about thousands and thousands of classified documents that the US will not comment on, as is their custom," Frattini said.
The governments of Canada, Norway, and Denmark also said they had been briefed by US officials.
Israel has also been warned of potential embarrassment from the release, which could include confidential reports from the US embassy in Tel Aviv.
Authorities in Ankara were also contacted, a senior Turkish diplomat told the AFP news agency, speaking on condition of anonymity.
According to Turkish media reports, the planned release includes papers suggesting that Turkey helped al-Qaeda fighters in Iraq, and that the US helped Iraq-based separatist Kurdish rebels fighting against Turkey.
The data could also harm Moscow's relations with Washington, the Kommersant newspaper reported Friday.
The confidential cables contain general assessments of the political situation in Russia and "unflattering characteristics" of Russian leaders, the respected business daily reported, citing a source at the whistle-blowing website.
"The documents include recordings of US diplomats' conversations with Russian politicians, assessments of Russia's most notable events, and analyses of what is happening in the country and in its domestic and foreign politics," the newspaper wrote.
Russia's Foreign Minister Sergei Lavrov said that his office has not been officially informed by Washington about the impending file dump, which he blamed on "little thieves running around the internet."
"They steal secret documents there, but we do not get the same thing here - or at least not to the same extent," the Interfax news agency quoted Lavrov as saying.
The files are also expected to include thousands of diplomatic cables reporting corruption by politicians in Afghanistan and other Central Asian nations.
Officials in several countries, including the UK, have issued defence advisory notices to contain the spill of data through media organizations covering the release.
"All governments no doubt will be putting pressure on media within their particular countries," Al Jazeera's Mike Hanna, reporting from Washington, said.
Our correspondent also said "intelligence agencies have been conducting a forensics exercise" to determine what sensitive information will be leaked.
Hanna said that the expected data dump could directly impact on current diplomatic engagements.
The Obama administration said earlier this week that it had alerted Congress and begun notifying foreign governments that the website was preparing to release a huge cache of diplomatic cables whose publication could give a behind-the-scenes look at American diplomacy around the world.
"WikiLeaks are an absolutely awful impediment to my business, which is to be able to have discussions in confidence with people"
James Jeffrey, US ambassador to Iraq
WikiLeaks has said the release will be seven times the size of its October leak of 400,000 Iraq war documents, the biggest leak to date in US intelligence history.
The site also published 77,000 classified US files on the Afghan conflict in July.
The US says it has known for some time that WikiLeaks held the diplomatic cables slated for release. Thus far, no one has been charged with passing them to the website, but suspicion focuses on Bradley Manning, a US army intelligence analyst arrested in Iraq in June and charged over an earlier leak.
"WikiLeaks are an absolutely awful impediment to my business, which is to be able to have discussions in confidence with people," James Jeffrey, US ambassador to Iraq, said. "They will not help, they will simply hurt our ability to do our work here."
He said that anyone whose "confidential discussions find their way into the press is going to be very unhappy and very upset".
Admiral Mike Mullen, the most-senior US military commander, has urged WikiLeaks to stop its release of documents, according to a transcript of a CNN interview set to air on Sunday.
"I would hope that those who are responsible for this would, at some point in time, think about the responsibility that they have for lives that they're exposing and the potential that's there and stop leaking this information."