The US government has ordered a new investigation into inadmissible questioning techiques used on terror suspects by the CIA.

Attorney-general Eric Holden has appointed a special prosecutor to investigate possible transgressions by CIA operatives. The previous administration under President George W. Bush had decided to refrain from an investigation.

The appointment of the special federal prosecutor John Durham was triggered by reports from 2004 and 2005 which were published on Monday. They describe, for instance, how CIA interrogators threatened Khalid Sheikh Mohammed, the mastermind of the September 11 attacks, by saying his children would be killed if there was any new attack on the US.

President Barack Obama has appointed a specialist team to conduct future interrogations of terror suspects. It will be placed under immediate supervision of the National Security Council, a presidential advisory body.