Chicago: A court here has given a go ahead for a civil suit against former defence secretary Donald Rumsfeld by two Americans, who allege that they were tortured by the US military in Iraq.

According to the 2006 lawsuit, Donald Vance, a Navy veteran from Chicago, and Nathan Ertel blew the whistle on the security firm they worked for after they suspected payoffs were made to Iraqi sheiks to obtain government contracts.

But US military personnel held the two in jail cells in Camp Cropper near the Baghdad airport and subjected them to violence, sleep deprivation and extremes in light and sound, reports say.

The US Court of Appeals for the Seventh Circuit, based in Chicago, upheld the decision on Monday.

"If the plaintiffs' allegations are true, two young American civilians were trying to do the right thing by becoming whistleblowers to the US  Government, but found themselves detained in prison and tortured by their own government...," Judge David F Hamilton wrote.

"No secretary of defense in US history has been named in a civil lawsuit alleging torture that has made it to trial," Chicago attorney Michael Kanovitz, who is representing Vance, was quoted as saying by a paper.

"It's important because what the court does here affirms the very basis of Constitutional doctrine," Kanovitz said of the appeals court decision.

"There are three branches of government; you don't give absolute discretion to the executive branch."

Rumsfeld, 79, could ask the appeals court in Chicago to review its ruling or appeal the decision to the US Supreme Court. He was the Secretary of Defense from 2001 to 2006, under President George W Bush.