The US military has freed about 230 prisoners it was holding at Iraq's notorious Abu Ghraib jail in the second round of releases this year.
Remaining detainees are said to include scores of non-Iraqis
It said that those freed either no longer posed a security threat or would be vouched for by members of their own communities.
With some 9,000 prisoners freed last year and 260 released on 1 January, about 7,400 now remain in US custody.
Reports of prisoner abuse by US guards at Abu Ghraib caused outrage last year.
Most of the remaining prisoners are being held at Umm Qasr in the south, with about 2,400 held at Abu Ghraib, near Baghdad.
About 1,100 detainees have been "identified for prosecution" for crimes including
illegal possession of weapons and attacks on US-led foreign and Iraqi forces, a military statement said.
The military said the releases had been approved by a review board consisting of six Iraqi officials and three senior officers from the foreign forces.