"This case is part of our effort to bring accountability for torture and other serious violations of international law arising out of the so-called war on terror and invasion of Iraq," the Centre for Constitutional Rights, whose legal team is representing the Iraqi plaintiffs, said in a statement before the trial was due to begin.
"Our clients are Iraqi civilians who were ultimately released without ever being charged with a crime.
"They all continue to suffer from physical and mental injuries caused by the torture and other abuse they endured."
An artist's sketch of the trial in Virginia. Dana Verkouteren / AP