The US army released 126 Iraqi prisoners on Sunday.
This is the second largest release since the abuse of Iraqis being held at Abu Gharib Prison was exposed in April.
In Baghdad, 44 prisoners were released from an Iraqi National Guard base.
Since the war broke out U.S troops have imprisoned about 5,000 Iraqis.
Human Rights groups have claimed that many were arrested without proper reason.
A US army captain admitted that many mistakes were made but said procedures had been changed to rectify the problems.
The US military has released hundreds of prisoners after the exposure of the abuses committed by US troops at Abu Gharib prison.
Source: CRI