The suits filed by truckers and their families accuse Halliburton and a former subsidiary, Houston-based KBR, of knowingly sending a convoy into a dangerous area where six KBR drivers were killed and several others wounded on April 9, 2004.

A federal judge in Houston threw out the lawsuits in September 2006, saying the judiciary can't second-guess the military's battlefield decisions.

But the 5th U.S. Circuit Court of Appeals in New Orleans reversed that judge's ruling on Wednesday and sent the three cases back to the lower court for further proceedings.

A three-judge panel from the appeals court said it may be possible to resolve the lawsuits without making a "constitutionally impermissible review of wartime decision-making."

Cases spawned in a war zone involve constitutional issues and "practical considerations" that can prevent them from being resolved in court, Judge Leslie Southwick wrote in the panel's 29-page ruling.

"It appears, though, that these tort-based claims of civilian employees against their civilian employers can be separated from the political questions that loom so large in the background," Southwick added."

The 5th Circuit said the cases could still run into a constitutional roadblock as they progress.

"The litigation is not yet there, if it ever will be," Southwick wrote.

KBR split from Halliburton last year and operates as a separate, publicly traded company. At least 110 of KBR's employees have been killed in Iraq since it started working there under a multibillion-dollar military contract in 2003.

KBR spokeswoman Heather Browne said the company hadn't seen the ruling yet and couldn't comment on it.

Halliburton spokeswoman Cathy Mann said she couldn't comment on the ruling because "defense of this lawsuit is KBR's responsibility."

Several lawyers for truck drivers' families didn't immediately return calls for comment Wednesday evening.