A group holding four Western peace activists captive in Iraq since November said it was giving a "last chance" for its demands to be met, according to a new videotape showing the hostages that aired on Al-Jazeera news channel.
The Brigades of the Swords of Righteousness gave "a last chance for meeting demands of releasing Iraqi prisoners from the Iraqi and American prisons," Al-Jazeera said.
"Or else they will be killed," it said, quoting a statement from the group.
Briton Norman Kember, American Tom Fox and Canadians James Loney and Harmeet Singh Sooden were abducted in Baghdad on November 26.
The men were part of a delegation for the Christian Peacemaker Teams, a body that dispatches volunteers to crisis areas in a bid to reduce armed conflict.
Carroll’s fate unclear
The fate of seized US reporter Jill Carroll also remained uncertain, eight days after the expiration of a deadline to kill unless all Iraqi women detainees were freed from US custody.
Sunni Arab leader Adnan Dulaimi, whom Ms Carroll was supposed to have met on January 7, the day she was snatched, reiterated his call for her release.
"I renew my appeal to the captors of the American journalist to free her immediately following the release of the Iraqi detainees, as they no longer have any argument" to hold her, he said.
The US and Iraqi authorities have released 419 detainees held without trial, of which five were women. Four Iraqi women continue to be held in US-Iraqi run prisons.
The US authorities have denied there was any link between the release of the five women and Carroll's abduction and say they have no new information about the hostage.
"A joint Iraq-US review board recommends the release of detainees and some more could be released in the near future," Lieutenant Colonel Guy Rudisill, spokesman of US detention facilities in Iraq told AFP.
Two German engineers seized in Iraq this week appealed Friday to Germany to save their lives, as Dulaimi described their kidnapping as "an insult to Islam."
Rene Braeunlich and Thomas Nitzschke, kidnapped at gunpoint by men in army uniforms, were shown in a video aired by Al-Jazeera, surrounded by four masked men brandishing assault rifles from a group calling itself the Followers of Unity and Prophetic Tradition.
They were seized in the restive northern oil refinery city of Baiji, the same area where a Brazilian engineer was kidnapped a year ago. His fate remains unknown.
German weekly Der Speigel said their captors in the video demanded immediate withdrawal of the German embassy in Iraq and release of women detainees.
The magazine did not indicate how it had obtained the video, which it said was dated "Tuesday 10:08 am", or "just two hours after the kidnapping".
Al-Jazeera had said the kidnappers had not issued any conditions for the men's release.
Last week, two Kenyan telecommunications engineers were kidnapped in
Baghdad, but no information has been released on their status or whereabouts.
As the hostage crisis burgeoned, President Jalal Talabani's national security advisor Wafiq al-Sammaraie told Iraqi television that US forces were scheduled to meet with insurgent groups under the protection of the president.
An official at Talabani's office said "contacts with insurgents were established but a meeting is not fixed yet."
The US military could not confirm the upcoming meeting, but did announce that it had detained 20 suspected rebels after finishing a major operation along the western Euphrates valley.
Saddam trial
Meanwhile, the trial of ex-president Saddam is to resume on Sudnay after it was postponed on Tuesday.
A new chief judge, Rauf Rashid Rahman, will preside after his predecessor
Rizkar Mohammed Amin quit over criticism he was too lenient with the defendants.
The New York-based Human Rights Watch blasted the demands for Amin's dismissal as "nothing less than an attack on judicial independence."
In rebel violence, prominent academic Abdel Raziq al-Naas was gunned down as he left his university offices in Baghdad.
A policeman was killed and another wounded in a roadside bomb attack in the restive town of Fallujah.