A US military judge on Wednesday set a summer 2028 trial date for Khalid Sheikh Mohammed and three others accused of plotting the 9/11 attacks, more than a quarter century after what the US government has called 'the most egregious criminal act on American soil in modern history'.

The self-proclaimed "mastermind" of the 9/11 attacks, Khalid Sheikh Mohammed, will stand trial in June 2028, a military judge ruled Wednesday.

Khalid Sheikh Mohammed, the man accused of masterminding the September 11, 2001 terrorist attacks will finally face trial in 2028, a judge declared on Wednesday.

The former al Qaeda propaganda chief has been held at the Guantanamo Bay detention camp in Cuba for 20 years.