A huge cache of secret US military files today provides a devastating portrait of the failing war in Afghanistan, revealing how coalition forces have killed hundreds of civilians in unreported incidents, Taliban attacks have soared and Nato commanders fear neighbouring Pakistan and Iran are fuelling the insurgency.

The disclosures come from more than 90,000 records of incidents and intelligence reports about the conflict obtained by the whistleblowers' website Wikileaks in one of the biggest leaks in US military history. The files, which were made available to the Guardian, the New York Times and the German weekly Der Spiegel, give a blow-by-blow account of the fighting over the last six years, which has so far cost the lives of more than 320 British and more than 1,000 US troops.

Their publication comes amid mounting concern that Barack Obama's "surge" strategy is failing and as coalition troops hunt for two US naval personnel captured by the Taliban south of Kabul on Friday.

The war logs also detail:

• How a secret "black" unit of special forces hunts down Taliban leaders for "kill or capture" without trial.

• How the US covered up evidence that the Taliban have acquired deadly surface-to-air missiles.