US Defence Secretary Lloyd Austin on Friday rejected a plea deal with the accused of the September 11, 2001, attacks and two other alleged accomplices.
The plea deal had been reached earlier this week and would have allowed the defendants to avoid the death penalty.
“Effective immediately, in the exercise of my authority, I hereby withdraw from the three pretrial agreements that you signed on July 31, 2024 in the above-referenced case,” Mr Austin said in a signed memorandum.
Mr Austin also relieved the senior Department of Defence official who served as the overseer of the war court at Guantanamo Bay, according to the memorandum, published by the Pentagon.
“I have determined that, in light of the significance of the decision to enter into pretrial agreements with the accused in the above-referenced case, responsibility for such a decision should rest with me as the superior,” it read.
The news was first reported by The New York Times.
On Wednesday, Khalid Shaikh Mohammed, Walid bin Attash and Mustafa Al Hawsawi, being held by the US at the federal detention camp in Cuba, agreed to plead guilty in exchange for avoiding the death penalty.
It was announced in a letter to the families of September 11 victims, but the Pentagon did not release details of the plea deal.
The US agreement with the men came more than 16 years after their prosecution began.
The defendants have been accused of several crimes, including murder, terrorism and plane hijacking in the attack that killed 2,976 people in New York City, Washington and Pennsylvania.
Mr Mohammed, a US-educated engineer, is portrayed as the mastermind behind the terrorist attacks, while Mr bin Attash and Mr Al Hawsawi are accused of being his accomplices.
This is not their first time presenting plea conditions: their previous attempt, along with two other individuals, in September was rejected by President Joe Biden's administration.