US tightens security after leaks
The White House has ordered government agencies to tighten their handling of classified documents after the latest Wikileaks release.
The whistle-blower website has released more than 250,000 US diplomatic cables.
They offer candid views of foreign leaders and frank assessments of security threats.
Attorney General Eric Holder said there was an ongoing criminal investigation into the release and anyone found responsible would be prosecuted.
The US said the release was "reckless" and put the lives of diplomats at risk.
Government agencies have been ordered to tighten their procedures for handling classified information, ensuring that employees have access only to documents they need to do their jobs.
"The recent irresponsible disclosure by Wikileaks has resulted in significant damage to our national security," said the director of the Office of Management and Budget, Jacob Lew.
"Any failure by agencies to safeguard classified information... is unacceptable and will not be tolerated," he said in a directive.
The Pentagon has already said it is making its computer systems more secure to prevent future leaks.
The founder of Wikileaks, Julian Assange, said the US authorities were afraid of being held to account.
The cables are a huge sampling of communications between the US State Department and its embassies and consulates around the world.
The messages were sent between 1966 and 2010 but most are from this decade.
Among the revelations is a report that King Abdullah of Saudi Arabia, among other Arab leaders, urged the US to destroy Iran's nuclear facilities.
Iranian President Mahmoud Ahmadinejad dismissed the leak as US propaganda which would not affect Tehran's relations with its neighbours.
Other concerns aired in the cables include the possibility of Pakistani nuclear material falling into the wrong hands, allowing militants to make an atomic weapon. The widespread use of computer hacking by China's government is also reported.
The cables also contain blunt appraisals of their host governments, and unflattering pen portraits of world leaders.
US officials are said to have described Italian Prime Minister Silvio Berlusconi as feckless, vain and ineffective and sharing a close relationship with the "alpha dog", Russian Prime Minister Vladimir Putin.
President Nicolas Sarkozy of France is said to be thin-skinned and authoritarian, while German Chancellor Angela Merkel is described as risk-averse.
Meanwhile, Libya's Colonel Muammar Gaddafi always travels with a "voluptuous blonde" Ukrainian nurse, according to one of the cables.
European nations have roundly criticised the leaks, with France saying they represent a threat to democratic authority.
Pakistan's foreign ministry, meanwhile, condemned what it called "the irresponsible disclosure of sensitive official documents".
Wikileaks has posted only some of the 200 of the 251,287 messages it says it has obtained. However, the entire bundle of cables has been made available to five publications, including the New York Times and the UK's Guardian newspaper.
Other issues reportedly covered in the cables are:
* Iranian attempts to adapt North Korean rockets for use as long-range missiles
* Corruption in Afghanistan with concerns heightened when a senior official was found to be carrying more than $52m (£33m) in cash on a foreign trip
* Bargaining to empty the Guantanamo Bay prison camp - including Slovenian diplomats being told to take in a freed prisoner to secure a meeting with President Barack Obama
* Germany being warned in 2007 not to enforce arrest warrants for CIA officers involved in an operation in which an innocent German citizen with the same name as a suspected militant was abducted and held in Afghanistan
* US officials being instructed to spy on the UN leadership by Secretary of State Hillary Clinton
* Alleged links between the Russian government and organised crime, with intelligence agencies using underworld bosses to carry out operations
* Yemen's president talking to General David Petraeus (while he was responsible for US military operations in Central Asia and the Middle East as head of US Central Command) about attacks on Yemeni al-Qaeda bases and saying: "We'll continue saying the bombs are ours, not yours"
* Faltering US attempts to prevent Syria from supplying arms to Hezbollah in Lebanon
In a statement, the White House said: "Such disclosures put at risk our diplomats, intelligence professionals, and people around the world who come to the United States for assistance in promoting democracy and open government.
"President Obama supports responsible, accountable and open government at home and around the world, but this reckless and dangerous action runs counter to that goal."
No-one has been charged with passing the diplomatic files to Wikileaks, but suspicion has fallen on US Army private Bradley Manning, an intelligence analyst arrested in Iraq in June and charged over an earlier leak of classified US documents to Mr Assange's organisation.
The cables release is the third mass Wikileaks release of classified document; it published 77,000 secret US files on the Afghan conflict in July, and 400,000 documents about the Iraq war in October.
Wikileaks argues the release of the documents has shed light on the wars, including allegations of torture and reports that suggest 15,000 additional civilian deaths happened in Iraq.BBC News