The lawsuit was filed in 2004 on behalf of Iraqi nationals who say they or their relatives had been tortured or mistreated while detained by the U.S. military at the Abu Ghraib prison.

The plaintiffs sued CACI International Inc, which provided interrogators at Abu Ghraib, and L-3 Communications Holdings Inc's Titan unit, which provided interpreters to the U.S. military.

... the appellate panel found the two companies had government contractor immunity and the claims were preempted, based on a 1992 U.S. Supreme Court ruling and other precedents in the national security and foreign policy areas.

"During wartime, where a private service contractor is integrated into combatant activities over which the military retains command authority, a tort claim arising out of the contractor's engagement in such activities shall be preempted," Judge Laurence Silberman said in the ruling.