US Army Staff Sergeant Ivan Fredrick, the highest-ranking official to be tried so far in the Abu Ghraib prison scandal, was sentenced to eight years in prison and reduced to the rank of a private for his role in abusing inmates at the Iraqi prison.

The 38-year-old sergeant was also ordered to forfeit his pay and allowances and given a dishonourable discharge after he agreed to testify against others charged with abusing the prisoners, the US Central Command said in Washington on Thursday.

The two-day court martial proceedings against Frederick ended at a US military base in Baghdad on Thursday when Judge Colonel James Pohl delivered the terms of his sentence.

As per a pre-trial agreement, the sergeant will have to serve only 8 years of his ten-year sentence.

Frederick had pleaded guilty to conspiracy, dereliction of duty, mistreatment of detainees, assault on a detainee and commission of an indecent act, according to the CENTCOM.

The case came to light early this year when photos showing US soldiers torturing hooded Iraqi prisoners at Abu Ghraib were published, triggering criticism and outrage across the world.