A US military spokesman for detention facilities in Iraq said on Saturday they would be releasing some detainees in the next 10 to 15 days although he declined to give any numbers.
Last month, Iraq released more than 400 detainees, including five women, in a move widely seen as a response to demands from the kidnappers of US reporter Jill Carroll to free all female prisoners in Iraq.
Both US and Iraqi spokesmen strongly denied any link at the time.
Shortly after those releases, a new videotape from the kidnappers was broadcast by Aljazeera in which they broadened their demand to include all detainees, male or female.
Carroll, who was working for the Christian Science Monitor, was abducted in Baghdad on 7 January by a group calling itself the Brigades of Vengeance as she travelled to a meeting with a leading Sunni Arab politician.
Her fate, as well as that of German engineers Rene Braeunlich and Thomas Nitzschke, was uncertain on Saturday.
Meanwhile, Frank-Walter Steinmeier, the German foreign minister, used Aljazeera to issue a new appeal for the release of the two engineers on Friday.
Steinmeir said: "Angela Merkel, the German Chancellor, and myself call upon you, on behalf of all Germans, to release the two hostages without subjecting them to any pain".
Braeunlich and Nitzschke, who work for German gas equipment installation company Cryotec, were abducted near a main oil refinery in the northern town of Baiji on 24 January by armed men in military uniform.
Their kidnappers threatened on Tuesday to kill them unless Berlin cut all links with Baghdad within 72 hours. That deadline expired on Friday night.
The three hostages are among nearly 250 foreigners kidnapped in Iraq since the March 2003 military intervention. Many of them have been killed.
The fate of two Kenyan telecommunications engineers, abducted last month, and two Iraqi television journalists seized on Wednesday, also remained unknown.