The documents, which include over 400 interviews with US officials and insiders from the administrations of President Donald Trump and his two predecessors, revealed how senior officials hid evidence that the 18-year-old war was unwinnable and made rosy pronouncements they knew to be false, Xinhua news agency quoted The Washington Post as saying on Monday.
"We were devoid of a fundamental understanding of Afghanistan we didn't know what we were doing," a senior American official was quoted as saying.
US officials acknowledged that their war-fighting strategies were fatally flawed and that Washington wasted enormous sums of money trying to remake Afghanistan into a modern nation, according to the report.
"What did we get for this $1 trillion effort? Was it worth $1 trillion?" said a retired Navy SEAL and White House official under the George W. Bush and Barack Obama administration, in another interview.
"Osama (bin Laden) was probably laughing in his watery grave considering how much we have spent."
a US Army colonel who served as a counter-insurgency adviser to American military commanders, said: "Every data point was altered to present the best picture possible."
The Washington Post published the documents two days after the resumption of the US-Taliban talks in Qatar's capital city of Doha.
Nearly 2,300 US servicemen have been killed and over 20,000 wounded in Afghanistan since 2001.
( With inputs from IANS )