|The US could be embarrassed by the disclosure, since the cables contain negative perceptions about allies [Reuters]
The United States has taken the highly unusual step of sending a letter to WikiLeaks to warn against the imminent release of some three million secret US government documents, which it says will put "countless" lives at risk.
The US state department released the letter from Harold Hongju Koh, its top lawyer, on Saturday night. The letter to the whistle-blowing website’s founder, Julian Assange, argued that publishing the classified files would threaten global counterterrorism operations and jeopardise the US’s relations with its allies.
WikiLeaks has said the newest release - expected to be just hours away - will be seven times the size of the October publication of 400,000 Iraq war documents, the biggest leak to date in US intelligence history.
The classified documents reportedly cover correspondence between US diplomatic missions abroad and the state department in Washington and could reveal "unflattering" views that American officials held about close EU allies and countries like Russia, China and Saudi Arabia.
Governments around the world on Saturday braced for the publication of potentially embarrassing diplomatic cables, as Washington raced to contain the fallout.
US diplomats skipped their Thanksgiving holiday weekend and headed to foreign ministries hoping to stave off anger over the cables, which are internal messages that often lack the niceties diplomats voice in public.
The site also published 77,000 classified US files on the Afghan conflict in July.
'Violation of US law'
In the letter, Koh said the release will "place at risk the lives of countless innocent individuals,'' "place at risk on-going military operations,'' and "place at risk on-going cooperation between countries".
"You have undermined your stated objective by disseminating this matieral widely, without redaction, and without regard to the security and sanctity of the lives your actions endanger," he wrote.
Koh said WikiLeaks should return them to the US government and destroy any copies in its possession or in computer databases.
Steve Clemons discusses the diplomatic ramifications of the leak with Al Jazeera
"They were provided in violation of US law and without regard for the grave consequences of this action,'' he said.
The letter also said the US government would not cooperate with WikiLeaks in trying to scrub the cables of information that might put sources and methods of intelligence gathering and diplomatic reporting at risk.
Steve Clemons, a political strategist and director of the American Strategy Programme in Doha told Al Jazeera that the US reaction to this latest round of leaks has been stronger than in the past because of mainly diplomatic concerns.
"Certainly I wouldn’t take it to the level of lives lost on the battlefield. This is essentially diplomatic brouhaha," he said.
"I think also that the content of these documents is a lot about the gossip and innuendo and the nuance ... and there are going to be a lot of embarrassing things that come out of these documents.
"There are be political repercussions of the way foreign leaders are going to read these documents. And in that sense, you're going to see people, ranging from have everyone from [Asif Ali] Zadari In Pakistan, to, I understand, Nelson Mandela of South Africa has had some bad swipes taken at him in these cables, the Saudi king ... "
Whatever the consequences for the US, Clemons said the leaks are highlighting the extent to which governments' reliance on secrecy has become so pervasive.
"To a certain degree I think the US government, and other governments, have a lot of burden in this themselves. They have classified so much and expanded official secrecy so much, that it's very hard now to discriminate between the kinds of secrets governments should be keeping, and those kinds of things that should be put out into the public.
"Governments have been trying to hide themselves from embarrassment. And I think that's what WikiLeaks is trying to create a market reaction to and trying to change."
According to Der Spiegel, which was granted early access to the files, the release will contain more than 250,000 cables and 8,000 diplomatic directives - mostly from the last five years.
The German news magazine took down its article summarising the data dump after publishing it briefly online.
In addition to Der Spiegel, The New York Times, The Guardian, Le Monde and El País are said to have been allowed to review the files beforehand.
According to White House sources cited by a correspondent of the US website Politico, none of the documents are classified as 'Top Secret'. But reportedly six per cent are listed as 'Secret' and 40 per cent as "confidential".
Al Jazeera's Mike Hanna, reporting from Washington, said the leaks are from correspondence "between US diplomats and between US embassies ... not what is said about enemies, but about [US] friends".
He said the files could include particularly sensitive information previously "well out of the public view" about US diplomats' perceptions of crises in Israel and Palestine.
Hanna said that US officials have emphasised how national security - not just public embarrassment - is at stake in the WikiLeaks release.
Less than five per cent of the files are about EU nations, according to OWNI, a French news site with a live blog covering the "StateLogs".
Speculation has swirled on the inclusion of cables about US ties to separatist groups in Turkey, perceptions of the UK coalition government, and allegedly corrupt politicians in several countries.
Some British newspapers reported on Sunday that Louis Susman, the US ambassador, had briefed British officials about the likely contents of the files.
The documents could include reports from officials in Washington and diplomatic posts around the world about issues on which Britain and the US have collaborated closely, including the wars in Iraq and Afghanistan.
Members of the former Labour administrations of Gordon Brown and Tony Blair were bracing for the flood of millions of documents.
The Sunday Times newspaper quoted one government official as warning that British citizens in Muslim countries could be targeted in a backlash over any perceived "anti-Islamic" views expressed.
"The concern of the UK government is that some of the diplomatic conversations may contain certain phrases (critical) of certain sensitive places by either the US or us in which Britain might be portrayed as being hand in glove with the Great Satan to attack Islam," the official was quoted as saying.
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.
The US says it has known for some time that WikiLeaks was in possession of the diplomatic cables.
Some 2.5 million US government employees have access to SIPRNet - the US government's secure version of the civilian internet - where the files reportedly originated.
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."