WASHINGTON • US lawmakers, veterans and experts have expressed shock and resignation after a Washington Post report on Monday unveiled 18 years of distortion by American officials over the prosecution of the war in Afghanistan.

The documents - 2,000 pages of confidential notes and interviews from 400 people, from ambassadors to troops on the ground - exposed a constant parade of failures while three presidential administrations insisted the war was moving in the right direction.

"We must end the vicious, lethal cycle of misinformation and unspecified, unsupported strategies," Senator Richard Blumenthal, a Democrat and member of the Senate Armed Services Committee, said in response, calling for public hearings with Defence Secretary Mark Esper and other officials.

"The Senate Armed Services Committee should hold hearings on the state of the Afghanistan conflict and the infuriating details and alleged falsehoods reported," said Senator Josh Hawley, a Republican and member of the committee.

"The time to end this war and bring our troops home honourably is now," said Representative Max Rose, a Democrat and Afghanistan veteran.

Statements from lawmakers came amid veterans reconciling their war with a new lens through which to view it.

For Marine Corps veteran Dustin Kelly, the story reignites the agony of not knowing precisely what his comrades gave their lives for.

"The most traumatic experiences of our lives did not have to happen, our friends did not have to die on the other side of the planet," Mr Kelly, who served as a mortar man in Helmand province in 2010 to retake the Taleban's stronghold, told The Post on Monday.

The Pentagon denied intentions to mislead lawmakers and the public and said the "hindsight" from Lessons Learned, the confidential records collected by the Special Inspector-General for Afghanistan Reconstruction (Sigar), helped revise and inform their strategy.

Lieutenant-Colonel Thomas Campbell, a Defence Department spokesman, said in a statement that there had been no intent by the Department of Defence (DOD) to mislead Congress or the public.

"DOD officials have consistently briefed the progress and challenges associated with our efforts in Afghanistan, and DOD provides regular reports to Congress that highlight these challenges. The information contained in the interviews was provided to Sigar for the express purpose of inclusion in Sigar's public reports.

"We remain in Afghanistan to protect our national interests and ensure that Afghanistan is never again used as a safe haven for terrorists who threaten the United States," Lt-Col Campbell said.

General (Ret) David Petraeus defended the reports he made from Afghanistan during his tenure there as commander of US forces in 2010 and 2011. "I stand by the assessments I provided as the commander in Afghanistan," Gen Petraeus said in a statement to The Daily Beast. He added that improvements, "while very hard fought and fragile, were indisputable".

He added that "there was undeniable progress on the security front, and I stand by what I told Congress and the national security team during that time".

Mr Rob Williams, a former Army infantryman who served in two deployments to Afghanistan, said the mission was not any clearer years after defence secretary Donald Rumsfeld himself could not identify the enemy. "We did not know who we were fighting," he told The Washington Post on Monday, describing deployments in 2007 and 2011.

Mr Williams and other veterans wondered if the revelations in the report were not obvious to veterans the entire time.

Mr Kelly, the Marine Corps veteran, saw through one common Pentagon talking point - that fierce fighting indicated the desperation of insurgents - once his unit understood their Afghan mission was to essentially become a tourniquet on a war that had gone from bad to worse. "Nobody could have possibly looked at that and thought, 'yeah, we're winning'," he said.

Defence officials, commanders and government staffers had, from the start, underestimated the complexities of the fight, the papers revealed, and it spiralled out of control when the mission to dislodge Al-Qaeda fighters and Taleban militants morphed into something else.

The mission became nation-building on top of a superstructure of "kleptocracy" and mind-bending corruption, even down to the police patrolman level.

The result: 43,074 Afghan civilians killed, 2,300 US troops dead and 64,124 Afghan troops and policemen killed in the insurgency that may be as strong as it ever was.

A central tenet of the Pentagon's strategy - build the capacity of Afghan forces - was often rejected by commanders more attuned to fighting than training foreign troops.

That may have helped "doomed the whole effort from the start", said Mr Charles Duncan, a former Army signals intelligence officer who served in Afghanistan in 2013.

"I thought the war's absurdity was only visible to those of us at the lower levels," he said. "Now I know that our pessimism was shared by officials all the way up the chain of command, and yet we all acted as though the war was winnable."

Lawmakers used the report to call for ending the war in Afghanistan and to repeal the president's broad authority to strike terrorist groups that critics say has kept the war on terror on an endless trajectory.

WASHINGTON POST