Wikileaks is today expected to release 400,000 secret files on Iraq, dwarfing the whistleblower's hugely controversial dump of Afghanistan documents.
The website is expected to disseminate the information simultaneously through a selected newspaper in Britain, another in Germany and a third in the United States in an operation that has been planned for weeks.
The hoard of classified information is more than four times the size of the material on the war in Afghanistan that WikiLeaks published in July through the same media outlets.
That move triggered widespread condemnation because of fears that it endangered the lives of hundreds of Afghans who gave information to the US-led military by revealing their names and where they live.
Robert Gates, the US Defence Secretary, voiced this concern in a letter written to Senator Carl Levin, the chairman of the Senate Armed Services Committee, in August, which came to light in US media reports over the weekend. Mr Gates also concluded, however, that the release of some 70,000 classified documents did not reveal sensitive information.
A Pentagon spokesman said last night that the timing of the leak remained unclear but the department was ready for it happening as early as today or tomorrow. Other sources, however, said it might not happen for at least another week.
Before the publication of the Iraq files - which look set to be even more revealing than the Afghan data - the Pentagon set up a 120-strong team to determine the potential implications and fallout.
It was unclear whether the MoD had taken similar pre-emptive measures. In response to a question on the expected publication of the Iraq material, an MoD spokesman said: "We condemn all unauthorised releases of classified material."
The US has urged WikiLeaks to return the information, arguing that it poses a risk to national security.
The documents are expected to be released simultaneously by The New York Times, The Guardian and Der Spiegel, the same organisations that released the Afghanistan "War Logs".
WikiLeaks, which says it is a non-profit organisation funded by human rights campaigners, journalists and the general public, justified the release of the Afghan papers in the interests of documenting the history of the war. Julian Assange, the website's founder, claimed that all the documents had been checked for named informants and that 15,000 such files had been held back.
Controversy has dogged Mr Assange and his website since the release of the Afghanistan files. He was accused of rape and harassment in Sweden, with the investigation of the rape claims dropped and then revived in the space of a week. Mr Assange denied the allegations, saying that sex with the women was consensual. But the fallout has been damaging, with several key players on WikiLeaks resigning after the allegations surfaced.
The site also faces funding difficulties as it has been placed on watchlists for the US and Australian governments, meaning that collecting money through Moneybookers, its online agency, has been difficult. Its PayPal account was suspended earlier this year. The WikiLeaks website was last night shut down for maintenance.
The US and Britain led the push to invade Iraq in March 2003 to topple Saddam Hussein who they wrongly suspected of harbouring weapons of mass destruction.
More than 100,000 Iraqis were killed in the war and bloody insurgency that followed. Millions of civilians were displaced and many more suffered injuries, both physical and mental. On the coalition side, the US military lost more than 4,000 servicemen and women. The British toll was 179.
Seven years after the invasion, Britain has largely pulled out its troop presence, while the US aims to bring the remainder if its troops home by the end of next year.
Iraq, however, is far from stable having failed to form a new government more than seven months after its last election.