Thousands of Iraqis held without charge by the US on suspicion of links to insurgents or militants will be freed by the summer because there is little or no evidence against them.
Their release comes as the US prepares to turn over its detention system to the fledgling Iraqi government by early 2010.
In the six years since the war began, the military ultimately detained some 100,000 suspects, many of whom were picked up in US-led raids during a raging, bloody uprising that has since died down.
The effort to do justice for those wrongly held to begin with, some for years, also runs the risk of releasing extremists who could be a threat to fragile Iraqi security.
As part of an agreement between the two countries that took effect on January 1, Iraqi authorities have begun reviewing the cases of the detainees to decide whether to free them or press charges. About 13,300 remain behind barbed wire in US custody in Iraq.
But Iraqi judges have issued detention orders to prosecute only 129 of the 2,120 cases they have finished reviewing so far this year - or about 6%, according to US military data. As of yesterday, 1,991 detainees had been freed since January 1.
An Associated Press reporter embedded for two days at Camp Bucca, the largest US detention centre in Iraq, talked with military officials about preparations to shut it down.
"God willing, God willing," said Layla Rasheed after learning that her son, a former government worker from Baghdad, was likely to be released.
"He doesn't have anything to do with terrorists. I don't know why he was picked up."
The military also expected to release another 600 detainees by the end of March, a spokesman said.
The US detention policy has been unpopular in a country where many feel that thousands have been detained without cause, and where the Abu Ghraib prison abuse scandal will be remembered for a long time.
Iraq's biggest Sunni parliamentary bloc has called for the release of virtually all detainees, arguing that even those who were militants no longer pose a threat because so many Sunni groups have abandoned the insurgency.
"It's very easy to go back and say, 'Well, you rounded up all these innocent people'. Well, innocence has different shades," Brig Gen David Quantock, commander of the US detention system in Iraq, said this week.
"It's not like we have a choice - it is prosecute or release. So it's a huge undertaking right now to try to find as much evidence as we can. We're not going after all of them, we're going after a certain amount."
Those who have been freed since January 1 make up what Brig Gen Quantock called low-level threats that Iraqi security forces should be able to contain if they returned to insurgent groups.
Extremists will be the last to have their cases reviewed, giving the US time to compile evidence against what they consider the highest risk to Iraq's security.
Brig Gen Quantock cited the cases of about 3,000 detainees where US officials are scrambling to compile enough evidence to keep them locked up. Additionally, 2,400 detainees have already been convicted or are awaiting trial, a military spokesman said.
Most of the detainees - about 9,600 - are being held at Camp Bucca, a sprawling, dusty military facility a few yards north of the Kuwaiti border, about 340 miles south east of Baghdad. It is due to close this summer.
Its detainees included those whom Brig Gen Quantock called "the worst of the worst" - suspected al Qaida terrorists, Shiite militants and Sunni insurgents.
Then there are those like Sunni teacher Suhail Najim Abdullah, who was released from Camp Bucca last March after more than three years.
"They just simply apologised to me and said, 'You have been arrested mistakenly'," Mr Abdullah said. "They gave me a shirt and trousers and 20 dollars. It's like I started my life over from zero."
Many detainees locked up at Cuba's Guantanamo jail were innocent men swept up by US forces unable to distinguish enemies from non-combatants, a former Bush administration official said.
"There are still innocent people there," Lawrence Wilkerson, a Republican who was chief of staff to then-secretary of state Colin Powell, said. "Some have been there six or seven years."
Retired army colonel Mr Wilkerson, who first made the assertions in an internet posting on Tuesday, said he learned from briefings and by communicating with military commanders that the US soon realised many Guantanamo detainees were innocent but nevertheless held them in hopes they could provide information for a "mosaic" of intelligence.
Navy Cmdr Jeffrey Gordon, a Pentagon spokesman, declined to comment on Mr Wilkerson's specific allegations but noted that the military had consistently said that dealing with foreign fighters from a wide variety of countries in a wartime setting was a complex process.
The military has insisted that those held at Guantanamo were enemy combatants and posed a threat to the US.