An Army investigation into the Biden administration’s catastrophic withdrawal from Afghanistan last year found the White House and State Department were too late in reacting to the Taliban’s final offensive, according to a new report Tuesday.

Senior officials failed to understand the significance of the Taliban’s push toward Kabul and resisted efforts by military commanders to prepare an evacuation of embassy staffers and Afghan allies in the weeks before the capital fell, putting American troops involved in the bugout in greater danger, according to the Washington Post, which cited the 2,000-page investigative report.

The report also revealed previously unreported instances of violence directed at US forces, including a gun battle between Marines and Taliban fighters that killed two of the militants and another in which American troops killed a member of an elite Afghan unit and wounded six others after they fired on Americans.

The investigation began after 13 US service members and more than 180 Afghan civilians were killed in a ISIS-K suicide bomb attack on Aug. 26 outside Hamid Karzai International Airport.

The report, obtained under a Freedom of Information Act request, details the immense pressure American troops were under as thousands of Afghans streamed to the airport in a desperate attempt to flee the return of Taliban rule.

The speed with which Taliban fighters took over the country and swept into Kabul on Aug. 15 forced US commanders to enter into a security pact with the militant group and deploy about 6,000 troops to assist the existing force of 600 to protect US Embassy personnel, the report said.

US officials praised the bravery of the troops but criticized the administration’s handling of the evacuation, which left behind hundreds of Americans and Afghan allies.

Navy Rear Adm. Peter Vasely, ​the top US commander in Afghanistan during the withdrawal effort, told investigators that the military would have been “much better prepared to conduct a more orderly” operation “if policymakers had paid attention to the indicators of what was happening on the ground.”

Vasely added that Washington’s lack of attention to the Taliban’s swift advance “undermined commanders’ ability to ready their forces.”

Other military officials told Army investigators that although the operation appeared haphazard, planning inside the Defense Department had been ongoing for months.

The discussions presumably included discussions about using Bagram Air Base for the evacuations and sending Afghan government forces to help secure the road there, Marine Corps Brig. Gen. Farrell Sullivan said.

US officials have said the air base 30 miles north of Kabul was too far away and would have required a large troop presence to maintain. Instead, it was turned over to the Afghan government, which surrendered it to the Taliban weeks later.

“Everyone clearly saw some of the advantage of holding Bagram, but you cannot hold Bagram with the force level that was decided,” Marine Gen. Kenneth McKenzie, head of US Central Command, told the Washington Post.

After the US abandoned Bagram, which served as the hub of American military operations over the course of the 20-year war in Afghanistan, hordes of looters descended on the sprawling base and ransacked barracks and stole military equipment left behind.

McKenzie said he was “not surprised” that military commanders have varying opinions about the effectiveness of the evacuation.