The US defense secretary revoked plea deals Friday agreed to earlier this week with the accused mastermind of the Sept. 11 terror attacks and two alleged accomplices.

"Today, Secretary (Lloyd) Austin signed a memo reserving for himself the specific authority to enter into pre-trial agreements with the accused in the 9/11 military commission cases.

"In addition, as the superior convening authority, the Secretary has also withdrawn from the pre-trial agreements that were signed in those cases," the Pentagon said in a statement.

Khalid Sheikh Mohammed, Walid Muhammad Salih Mubarak bin Attash and Mustafa Ahmed Adam al-Hawsawi reached plea agreements with the US earlier this week.

The three accused were all charged in 2008 and in 2012 in connection with their alleged roles in the Sept. 11, 2001, attacks, which claimed more than 3,000 lives after al-Qaeda terrorists hijacked two planes and crashed them into the Twin Towers at the World Trade Center in New York City.

Ali Abdul Aziz Ali and Ramzi Bin al Shibh were similarly charged in the 9/11 attacks.