Washington (CNN) Confidential documents obtained by The Washington Post reveal that top US officials misled the American public about the war in Afghanistan in order to conceal doubts about the likelihood that the US could be successful in the nearly 20-year effort since its earliest days, the paper reported in a major investigation on Monday.

The Post said it obtained the more than 2,000 pages of documents through a Freedom of Information Act request made three years ago that sought to win access to the documents, which it said were part of a lengthy government report titled "Lessons Learned" that examined "the root failures" of the war effort through interviews with more than 600 people, including a number of foreigners connected to NATO and 20 Afghan officials. The first interviews for the report were conducted in 2014, according to the Post, which said seven parts of the report have been published since 2016.

The paper said the interviews "bring into sharp relief the core failings of the war that persist to this day" as "U.S. officials acknowledged that their warfighting strategies were fatally flawed and that Washington wasted enormous sums of money trying to remake Afghanistan into a modern nation."

"Several of those interviewed described explicit and sustained efforts by the U.S. government to deliberately mislead the public," the Post reported. "They said it was common at military headquarters in Kabul — and at the White House — to distort statistics to make it appear the United States was winning the war when that was not the case."

Lt. Col. Thomas Campbell, a Defense Department spokesperson, pushed back on the Post's reports of deception, telling CNN in a statement that "there has been no intent by DoD to mislead Congress or the public."

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