A 10-member military jury found Graner, 36, a former civilian prison guard, guilty on 10 charges, many of which were documented by photographs of sexual humiliation of naked male prisoners that shocked the world after they were leaked last year.

Graner stood at attention and looked straight ahead without any visible reaction as the verdict was read. He held his hands tightly clenched.

Because the jury altered one count to a lesser charge of assault, rather than use of force likely to produce death or grievous bodily harm, his maximum sentence was lessened to 15 years from a possible 17 and a half years, a prosecution spokesman said.

Defence attorneys said Graner himself was expected to testify when the sentencing phase of the trial resumes on Saturday.

In his closing argument, Graner's lawyer said the former Pennsylvania prison guard was following orders of military intelligence officials at Abu Ghraib outside Baghdad as part of a vital, larger US war effort in Iraq.

"Corp. Graner is a smart guy, professional and he was doing his job in Iraq," defence attorney Guy Womack told the court. "Now the government would ask a corporal, an E4, one of the junior people there, to take the hit for it."

The prosecution argued that Graner and others in his unit acted without orders for their own gratification.

Meanwhile, an American soldier was sentenced on Friday to a year in jail for the murder of a severely wounded Iraqi teenager in a Baghdad slum district during a Shia uprising last year, the US military said.

"Staff Sergeant Cardenas Alban was convicted on one count of murder and one count of conspiracy to murder at a court martial at the 1st Cavalry Division courthouse at Camp Liberty today," a military spokesman said.