It did not give other details on the release that took place on Sunday.
Last month it released more than 400 detainees from various US- and Iraqi-run prisons, while on Saturday a US spokesman said a fresh batch of detainees were to be released within a fortnight.
A US military spokesman for detention facilities in Iraq said on Saturday: "We will be releasing some detainees in the next 10 to 15 days." He declined to give any numbers.
The spokesman said it was unclear if any of the four remaining women detainees would be among those freed.
Last month's release was seen as a move in response to demands from the kidnappers of US reporter Jill Carroll for the freeing of all female prisoners in Iraq.
Both US and Iraqi spokesmen strongly denied any link at the time.
Carroll was kidnapped on 7 January in Baghdad from outside the office of a prominent Sunni politican.
Her captors earlier demanded the release of female detainees from prisons, and reaffirmed their demands in a new videotape broadcast by Aljazeera last week.
Her fate still remains unknown.
Carroll is among nearly 250 foreigners kidnapped in Iraq since the March 2003 invasion. Many of them have been killed.