More than 90,000 secret US military records have been leaked to the media, revealing hidden details of the war in Afghanistan, newspapers report.
The documents are said to include unreported killings of Afghan civilians as well as covert operations by US special forces against Taliban leaders.
UK daily The Guardian and the New York Times say the records were shown to them and to German weekly Der Spiegel by online whistle-blower Wikileaks.
The US has condemned the leaks.
In a statement, 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”.
The reports come as Nato says it is investigating reports that as many as 45 civilians died in an air strike in Helmand province on Friday.
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