Rare footage from inside a Baghdad prison camp shows hundreds of inmates packed into wire-mesh tents, protesting their innocence.
"I have been jailed for two years and have never been put before a judge or court!" one prisoner is shown shouting.
The video pictures were given to Reuters Television on Saturday by the office of Sunni Arab Vice President Tareq al-Hashemi, who visited the Rusafa prison compound in eastern Baghdad with his Shi'ite counterpart.
Hashemi told the prisoners that the authorities were working to speed up their cases and he promised better treatment.
The footage showed row upon row of outdoor tents made of wire mesh and covered with white plastic sheeting, each about the size of a basketball court and housing dozens of inmates.
"We are not asking for food or water. Just free us. We have committed no crimes," said one inmate.
Prisoners, some stripped to their waists, pressed up against the mesh walls and shouted their innocence. Some chanted Saddam-era Iraqi nationalist slogans.
Hashemi said: "We will not accept this injustice. It is a shame on all of us. Be patient. All of your cases will be heard."
At one point he added: "You are lucky to be here. At least you have security. Those outside do not even have security."
U.S. forces and Iraq's own security forces have imprisoned tens of thousands of detainees without charge in the four years since the fall of President Saddam Hussein.
Many of the prisoners held by both U.S. and Iraqi authorities are Sunni Arabs accused of participating in the insurgency against the Shi'ite-led government, and their treatment is an emotional issue for the Sunni Arab community.
The treatment of prisoners has been especially resonant in the wake of the Abu Ghraib scandal in 2004, when pictures showed U.S. troops sexually humiliating detainees. Washington says such abuse has stopped and those responsible were punished.
The director of the prison visited by Hashemi, Major-General Jumah Hussein, told Reuters by telephone the tented camp was opened a month ago to relieve overcrowding at prisons throughout Iraq, and the complex now held 2,779 prisoners.
He said the tents were built "according to international standards", with air conditioning and 24-hour electricity.
"The prisoners arrived just a month ago. It is not our fault that some have been held for a year or two years without their cases going before a judge. We are drawing up lists of all the prisoners and will put all their cases before a court," he said.
The U.S. military says it is now holding 23,000 Iraqis, 19,000 of them at Camp Bucca, a giant prison camp in southern Iraq. Washington says its own prisoners are covered by U.N. Security Council resolutions which allow its forces to hold them without charge as long as they are deemed a threat.
Although U.S. forces are not responsible for prisoners held by Iraqi authorities, "we encourage them to treat their prisoners with as much respect as is seen in the West," said U.S. military spokesman Lieutenant-Colonel Christopher Garver.
The Shi'ite-run Interior Ministry was criticised over the treatment of detainees in 2005 after U.S. forces said they discovered secret cells in which detainees had been tortured.