Published: Jul 26, 2010 1:14 AM EDT
Updated: Jul 25, 2010 10:14 PM EDT

WASHINGTON (AP) - The New York Times and London's Guardian newspaper are reporting one of the biggest leaks of classified documents in military history.
      
The papers reveal fears among NATO leaders that Pakistan and Iran are fueling the insurgency in Afghanistan. The also document unreported incidents of Afghan civilians killed by NATO forces and covert special forces operations against Taliban figures.
      
The online whistle blower organization Wikileaks provided the Times, the Guardian and the German weekly Der Spiegel with early access to the 90,000 documents they're releasing.

A U.S. official it may take days to comb through all the documents. The source of the leak is believed to be a U.S. Army analyst who was arrested in Iraq and has been charged with leaking classified information.