More than 90,000 leaked US military records have been published on the website Wikileaks, reportedly revealing hidden details of the Afghanistan war.
Three major news publications which have been shown the documents say they include unreported killings of Afghan civilians.
The huge cache of classified papers is described as one of the biggest leaks in US military history.
The White House has condemned the leaks as "irresponsible".
Reports by the UK daily The Guardian, the New York Times and the German weekly Der Spiegel say the leaked papers reveal Nato concerns that neighbouring Pakistan and Iran are helping Taliban insurgents in Afghanistan.
The Pakistani ambassador in Washington said the "unprocessed" reports did "not reflect the current onground realities".
"The United States, Afghanistan and Pakistan are strategic partners and are jointly endeavoring to defeat Al-Qaeda and its Taliban allies militarily and politically," said Husain Haqqani.
The reports also suggest:
- The Taliban has had access to portable heat-seeking missiles to shoot at aircraft.
- A secret US unit of army and navy special forces has been engaged on missions to "capture or kill" top insurgents.
- Many civilian casualties have gone unreported, both as a result of Taliban roadside bombs and Nato missions that went wrong.
The BBC's diplomatic correspondent Bridget Kendall says that although the documents reveal no dramatic new insights, they show the difficulties of the war and the civilan death toll.
The reports offer an unvarnished and grim picture of the Afghan war, she adds.
In a statement, US National Security Adviser Gen James Jones said such classified information "could put the lives of Americans and our partners at risk, and threaten our national security".
He said the documents covered the period from 2004 to 2009, before President Obama "announced a new strategy with a substantial increase in resources for Afghanistan".
BBC News
