* Lawsuit filed in 2004 over Abu Ghraib jail mistreatment
* At issue is whether military contractors have immunity
* Obama administration opposed appeal by Iraqis
WASHINGTON, June 27 (Reuters) - The U.S. Supreme Court on Monday let stand the dismissal of a lawsuit claiming that employees of two defense contractors took part in the torture and abuse of Iraqis at the Abu Ghraib prison in Iraq.
The justices rejected an appeal by a group of 250 Iraqis seeking to reinstate their lawsuit against CACI International Inc (CACI.N), which provided interrogators at Abu Ghraib, and L-3 Communications Holdings Inc's (LLL.N) Titan unit, which provided interpreters to the U.S. military.
The lawsuit was filed in 2004 on behalf of the Iraqis who said they or their relatives had been tortured or mistreated while detained by the U.S. military at the Abu Ghraib prison outside Baghdad. They said contractor employees participated in the abuse, a claim denied by the companies.
The justices declined to review a federal appeals court ruling that dismissed the lawsuit because the companies had immunity as government contractors and because the suit was pre-empted by U.S. national security and foreign policy law.
Attorneys for the Iraqis argued the contractors were not immune because the alleged torture at the prison fell outside the scope of the work they had agreed to perform.
In appealing to the Supreme Court, the attorneys said victims of torture may proceed with lawsuits against private parties and corporations can be held liable for torture under international law.
Attorneys for CACI and L-3 opposed the appeal, said the appeals court's rejection of the claims was correct, and said further Supreme Court review of the case was unwarranted.
The Obama administration supported the companies and said the appeal should be denied.
After what happened at Abu Ghraib, the U.S. government has various tools available to punish those who commit torture and to compensate those subjected to abusive treatment while detained by the U.S. military, administration attorneys said.
The Supreme Court turned down the appeal in a brief order with any comment.
The Supreme Court case is Haidar Saleh v. Titan Corp, No 09-1313. (Reporting by James Vicini, Editing by Vicki Allen)