The chaotic withdrawal has long been a target of Republican criticism, and in a memo, Hegseth said that he has concluded that a "comprehensive review" was needed to ensure that a "complete picture is provided to the American people".
Donald Trump's Defence Secretary Pete Hegseth has launched a Pentagon investigation into the 2021 withdrawal of US forces from Afghanistan.
The chaotic withdrawal has long been a target of Republican criticism, and in a memo, Hegseth said that he has concluded that a "comprehensive review" was needed to ensure that a "complete picture is provided to the American people".
In his memo, the Pentagon chief wrote that the review would ensure that accountability for the troop withdrawal was met.
“On August 26, 2021. President Biden's administration led a chaotic withdrawal of U.S. military and embassy officials from Afghanistan that led to the deaths of 13 U.S. service members and 170 civilians in a suicide bombing at the Kabul International Airport's Abbey Gate.”
"I have concluded that we need to conduct a comprehensive review to ensure that accountability for this event is met and that the complete picture is provided to the American people," stated the memo.
According to it, a special review panel will be tasked with "thoroughly" examining the events that led to what it calls "one of America's darkest and deadliest international moments".
It will examine "previous investigations, to include but not limited to, findings of fact, sources, witnesses, and analyse the decision-making that led to one of America's darkest and deadliest international moments".
"This team will ensure ACCOUNTABILITY to the American people and the warfighters of our great Nation," it added.
In August 2021, after a 20-year stint in Afghanistan, US troops were pulled from the nation by the then-US president.
Announcing the withdrawal, Biden at the time said that American troops were sent to Afghanistan to "make sure al Qaeda could not use Afghanistan as a base from which to attack us again," and not for "nation building".
"We went to Afghanistan almost 20 years ago with clear goals: get those who attacked us on September 11th, 2001, and make sure al Qaeda could not use Afghanistan as a base from which to attack us again," he said.
"We did that. We severely degraded al Qaeda in Afghanistan. We never gave up the hunt for Osama bin Laden, and we got him. That was a decade ago," said Biden, adding "Our mission in Afghanistan was never supposed to have been nation-building. It was never supposed to be creating a unified, centralised democracy."
"Our only vital national interest in Afghanistan remains today what it has always been: preventing a terrorist attack on American homeland."
The US troop withdrawal paved the way for the Taliban to return to power, two decades after their first government was toppled by American forces in the wake of the September 11 attacks.