Amnesty's USA executive director Larry Cox said the human rights group was "disturbed by the fact that commanding officers have been granted immunity to testify rather than held accountable for crimes committed under their watch."

Cardona hugged his military defense lawyer Major Kirsten Mayer, and civilian attorney Harvey Volzer, and bear-hugged former comrades in the public gallery after the sentence was handed down.

Volzer was heard to tell his client "justice" had been served.

Former comrades and commanding officers acting as character witnesses portrayed Cardona as him as a brave and resourceful soldier during his sentencing hearing.

But prosecutors implored the panel to consider how the punishment would be seen in the outside world.

"We can win all kinds of battles but end up losing the whole dang war because there are bone-headed decisions," said prosecutor Major Matthew Miller.

Another dog handler, Sergeant Michael Smith, 24, was jailed for six months in March and demoted to the rank of private over the scandal.

Some critics of the US administration and the Pentagon have complained that no senior officers have been prosecuted over Abu Ghraib. Cardona's defense argued the use of dogs to interrogate prisoners was condoned by his superiors.

The defense also said there was no clear chain of command at chaotic Abu Ghraib and argued soldiers there were under intense pressure from military and political leaders desperate intelligence.

The Abu Ghraib scandal erupted in 2004 after photographs were leaked to the press showing US guards mistreating and sexually humiliating prisoners. Some pictures showed naked inmates cowering in front of unmuzzled dogs.

Cardona's trial heard testimony from the highest-ranking officer yet questioned in court over the affair, General Geoffrey Miller, who said he had only recommended the use of dogs for keeping order at the prison.

Lieutenant General Ricardo Sanchez, commander in Iraq at the time, and other senior officers have been cleared of responsibility.

Specialist Charles Graner and his girlfriend of the time, Private Lynndie England, became the public face of the abuse scandal and both were jailed.