The Biden administration asked a federal appeals court Tuesday to block a plea deal for Khalid Sheikh Mohammed and two co-defendants accused of 9/11 attacks that would have allowed them to avoid the possibility of the death penalty.

The Justice Department argued in a brief filed with the U.S. Court of Appeals for the District of Columbia Circuit that the government would be irreparably harmed if it accepted the plea deal. The Justice Department said the government would be deprived of a public trial and the opportunity to “seek the death penalty against three men accused of a heinous act of mass murder that left thousands dead and shocked the nation and the world.”

Defense Secretary Lloyd Austin sought to scrap the plea deal but was overruled by a military judge at Guantanamo Bay and a military appeals panel. They said Austin did not have the authority to scrap the plea deal after senior Pentagon officials in charge of Guantanamo approved it last July.

Mohammed was scheduled to plead guilty on Friday, and his two co-defendants were scheduled to plead guilty next week.

The Justice Department’s brief said the defendants would not be harmed by a short delay because the prosecution has been ongoing since 2012 and the plea deal would likely result in long prison sentences, possibly life.

“A short delay to allow this court to consider the merits of the government’s motion in this important case will not materially harm the defendants,” the government argued.