The guilty plea was delayed due to government opposition

The US government has managed to temporarily block an accused mastermind of the 9/11 attacks from pleading guilty amid a dispute over the terms of a plea deal.

Last summer, Khalid Sheikh Mohammed and two other defendants reached a deal to plead guilty to all charges in exchange for not facing the death penalty.

In a filing with a federal appeals court, the government argued that irreparable harm would result if the motions were granted.

The three-judge panel said they needed more time to hear the case and adjourned the case. They emphasized that the delay “should in no way be considered as a decision on the merits” of the case.

It comes after a military judge and appeals panel rejected an earlier move by Defense Secretary Lloyd Austin cancel agreementswhich was signed by a senior official appointed by him.

Nearly 3,000 people died in the September 11, 2001, terrorist attacks, when hijackers hijacked passenger planes and crashed them into the World Trade Center in New York and the Pentagon outside Washington. Another plane crashed in a field in Pennsylvania after passengers fought back.

The three men have been in custody in the United States for more than 20 years, and preliminary hearings in the case lasted more than a decade.

Arguments focused on whether the evidence was tainted by the torture the defendants faced in CIA custody after their arrest.

After the arrest in 2003 Mohammed was subjected to simulated drowning, or “waterboarding”, 183 times in secret CIA prisons. Other so-called “advanced interrogation techniques” included sleep deprivation and forced nudity.

Families of some of those killed in the Sept. 11 attacks criticized the agreements for being too lenient or opaque, while others saw them as a way to advance a complex and long-running case.

Those traveling to the US naval base at Guantanamo Bay in Cuba to watch Muhammad’s guilty plea spoke to reporters when news of the delay was announced.

“The US government failed families again on 9/11. They had an opportunity to do the right thing and they chose not to do it,” said Tom Resta, whose brother, sister-in-law and their unborn child died in the attacks.

The government argued that taking the deals would mean it was denied the chance to “seek the death penalty against three men accused of a horrific mass killing that left thousands dead and shocked the nation and the world.”

“A brief stay to allow this court to consider the merits of the government’s request in this important case would not materially prejudice the defendants,” it said.

In its response, Mohamed’s team said the deal offered “the first opportunity for real closure” in nearly a quarter of a century. It said the plea negotiations, which took place over two years, “had the direct involvement of the White House.”

In its decision late Thursday, the Federal Court of Appeal said its ruling was intended to give the justices time to be fully briefed and hear arguments “on an expedited basis.”

The delay means the case will now be handed over to the incoming Trump administration.

Full details of the agreements reached with Mohammed and his two co-defendants have not been released.

At his Guantanamo Bay hearing on Wednesday, his legal team confirmed that he had agreed to plead guilty to all charges.

If the deals are approved and the pleas are accepted by the court, the next step is to appoint a military jury, known as a panel, to hear evidence at a sentencing hearing.

In court Wednesday, lawyers described it as a form of open trial where survivors and family members of those killed would be given the opportunity to testify.

Under the agreement, the families will also be able to ask questions of Mohamed, who will have to “answer their questions fully and truthfully,” the lawyers said.