US judge blocks 9/11 mastermind Khalid Sheik Mohammed's testimony in bin Laden son-in-law's case

A US judge blocked America's most high-profile terror detainee yesterday from testifying in a New York courtroom to defend Osama bin Laden's son-in-law.

"I have considered this very carefully. It's much ado about nothing. It's not admissible," Judge Lewis Kaplan told the southern district court in Manhattan.

Suleiman Abu Ghaith, who married bin Laden's daughter Fatima, is on trial for conspiracy to kill Americans, conspiracy to support and supporting terrorists.

The 48-year-old from Kuwait denies the charges. He faces life imprisonment if convicted by a jury at the trial, which is expected to conclude within days.

His defence lawyers extracted 14 pages of written testimony from Khalid Sheikh Mohammed (pictured), the self-styled 9/11 mastermind held at Guantanamo Bay, saying that it disputed key elements of the prosecution's case.

Mohammed had claimed Abu Ghaith never played a military role in Al-Qaeda and had nothing to do with a 2001 plot to bomb a transatlantic US passenger jet. He refused to testify by audio or video-link from the US military prison.