US NAVAL BASE AT GUANTANAMO BAY  - Self-proclaimed 9/11 mastermind Khalid Sheikh Mohammed and two alleged co-conspirators skipped the second day of their pre-trial hearing at Guantanamo Bay on Tuesday.

Mohammed, who on Monday said he did not "think there's any justice in this court," his nephew Ali Abd al-Aziz Ali, and Mustapha al-Hawsawi all chose not to participate at the request of their lawyers, military judge James Pohl said.

The remaining two accused, Yemenis Ramzi Binalshibh, who rented a flat in Germany with chief 9/11 airliner attacker Mohammed Atta, and Walid bin Attash, did appear in court for the second day of the hearing.

Long-delayed efforts to try Mohammed, known as KSM, and his Al-Qaeda co-defendants finally got under way Monday, more than eleven years after the September 11 attacks and nine-and-a-half years after his capture.

KSM is accused of orchestrating the hijacked airliner plot that left 2,976 people dead, while his alleged Al-Qaeda accomplices are charged with providing funding and other support for those who crashed the planes.

Initially set for June, the pre-trial hearing has been delayed on several occasions for reasons including Ramadan, scheduling conflicts, a train derailment that sparked an Internet outage at the base and a tropical storm.