WASHINGTON, United States (AFP) — United States (US) Defence Secretary Lloyd Austin on Friday scrapped a plea agreement with 9/11 mastermind Khalid Sheikh Mohammed, just two days after the announcement of a deal that reportedly would have taken the death penalty off the table.

Deals with Mohammed and two alleged accomplices announced Wednesday had appeared to have moved their long-running cases toward resolution — but sparked anger among some relatives of those killed on September 11, 2001, as well as criticism from leading Republican politicians.

“I have determined that, in light of the significance of the decision to enter into pre-trial agreements with the accused… responsibility for such a decision should rest with me,” Austin said in a memorandum addressed to Susan Escallier, who oversaw the case.

“I hereby withdraw from the three pre-trial agreements that you signed on July 31, 2024 in the above-referenced case,” the memo said.

The cases against the 9/11 defendants have been bogged down in pre-trial manoeuvrings for years, while the accused remained held at the Guantanamo Bay military base in Cuba.

The New York Times reported this week that Mohammed, Walid bin Attash and Mustafa al-Hawsawi had agreed to plead guilty to conspiracy in exchange for a life sentence, instead of facing a trial that could lead to their executions.

Much of the legal jousting surrounding the men’s cases has focused on whether they could be tried fairly after having undergone methodical torture at the hands of the Central Intelligence Agency (CIA) in the years after 9/11.

The plea agreements would have avoided that thorny issue, but they also sparked sharp criticism from political opponents of President Joe Biden’s administration.

Republican lawmaker Mike Rogers, the chairman of the House Armed Services Committee, sent a letter to Austin that said the deals were “unconscionable,” while House Speaker Mike Johnson said they were a “slap in the face” to the families of the nearly 3,000 people killed in the September 11 attacks.

And Republican presidential candidate Donald Trump’s running mate, JD Vance, described the agreements as a “sweetheart deal with 9/11 terrorists,” saying during a campaign rally: “We need a president who kills terrorists, not negotiates with them.”

Mohammed was regarded as one of Al-Qaeda chief Osama bin Laden’s most trusted and intelligent lieutenants before his March 2003 capture in Pakistan. He then spent three years in secret CIA prisons before arriving at Guantanamo in 2006.

The trained engineer — who has said he masterminded the 9/11 attacks “from A to Z” — was involved in a string of major plots against the United States, where he had attended university.

Bin Attash, a Saudi of Yemeni origin, allegedly trained two of the hijackers who carried out the September 11 attacks, and his US interrogators also said he confessed to buying the explosives and recruiting members of the team that killed 17 sailors in an attack on the USS Cole.

After the US invasion of Afghanistan in 2001, he took refuge in neighbouring Pakistan and was captured there in 2003. He was then held in a network of secret CIA prisons.

Hawsawi is suspected of managing the financing for the 9/11 attacks. He was arrested in Pakistan on March 1, 2003, and was also held in secret prisons before being transferred to Guantanamo in 2006.

The United States used Guantanamo, an isolated naval base, to hold militants captured during the “War on Terror” that followed the September 11 attacks in a bid to keep the defendants from claiming rights under US law.

The facility held roughly 800 prisoners at its peak, but they have since slowly been repatriated to other countries. Biden pledged before his election to try to shut down Guantanamo, but it remains open.