Khalid Sheikh Mohammed, the alleged mastermind behind the September 11, 2001, terrorist attacks in the United States, has been given a trial date nearly 25 years after the attacks.

A US Air Force judge ordered on Wednesday that Mohammed and three co-defendants stand trial before a military tribunal in June 2028. The proceedings will take place at the US military commission at Guantanamo Bay, where Mohammed has been detained for nearly two decades.

The case has faced repeated delays because of lengthy legal disputes, including arguments over confessions that US authorities obtained after the defendants were subjected to torture. Lawyers have also debated where the men should be tried and how evidence from their years in detention should be handled.

Mohammed had previously reached a plea agreement in which he agreed to plead guilty in exchange for avoiding the death penalty. However, the agreement was later rejected, leaving the case on course for a trial.

The four defendants facing trial are Mohammed, Walid Muhammad Salih Mubarak bin 'Atash, Mustafa Ahmed Adam al Hawsawi, and Ali Abdul Aziz Ali. They are accused of playing major roles in the planning and preparation of the September 11 attacks.

Mohammed, who was born in Kuwait in 1965, studied mechanical engineering at a US university and later worked as an engineer for the Qatari government. US intelligence officials have also linked him to earlier plots against US interests and to other major terrorist attacks.

He is accused of helping plan the 1993 World Trade Center bombing, the 2002 Bali bombings in Indonesia and the murder of US journalist Daniel Pearl, in addition to the September 11 attacks.

Mohammed faces charges connected to the deaths of 2,977 people in the September 11 attacks, including murder, terrorism, aircraft hijacking and attacks on civilians.

Because the charges are classified as war crimes, the defendants will be tried before a military tribunal rather than a conventional civilian court. If convicted, Mohammed could face the death penalty, although such a sentence would likely lead to years of appeals and further legal proceedings.