The two engineers were shown seated on the ground with at least four armed men behind them. The tape was dated Jan. 24, the day they were abducted in the northern industrial city of Beiji.
The two men were seen speaking but Al-Jazeera did not broadcast any audio and the station did not report any demands beyond the German government working for their release.
The tape showed a handwritten black banner "Supporters of Tawhid and Sunnah Brigades." Tawhid is the Arabic word for monotheism and Sunnah refers to the teachings of the prophet Muhammad.
The victims, identified by relatives as Thomas Nitzschke and Rene Braeunlich, arrived in Iraq on Jan. 22 and only planned to remain "for a short time," the German Foreign Ministry said.
They were working for a German company in Leipzig which has a commercial relationship with an Iraqi government-owned detergent company in Beiji, an industrial town about 155 miles north of Baghdad.
In Berlin, Deputy Foreign Minister Gernot Erler told ARD television that no contact had been made with the kidnappers and a ministry crisis unit "is working constantly to save the two engineers."
In other developments:
At least five foreigners have been kidnapped in Iraq this month — including two Kenyan communications engineers missing after an ambush in Baghdad on Jan. 18 and American journalist Jill Carroll, who was seized Jan. 7 in the capital. Her translator was killed.
Carroll's kidnappers have threatened to kill the 28-year-old freelancer unless all Iraqi women are freed from custody.
The U.S. militaryThursday, and a top Iraqi police official, Maj. Gen. Hussein Kamel, expressed hope the move might help win Carroll's freedom.
However, U.S. officials insisted the release was not linked to the demand by Carroll's kidnappers that all women detainees be freed. The women were among 420 detainees being released Thursday and Friday, the U.S. command said.
Kamal, head of intelligence at the Interior Ministry, said freeing the Iraqi women "might assist in releasing Carroll," a freelance reporter for The Christian Science Monitor.
"Any announcement may not benefit the case because of its sensitivity, but we can say, `God willing,' that she will be released," Kamal told The Associated Press.
U.S. Embassy spokesman Tom Casey said American authorities were not convinced the release of the Iraqi women would have any influence over the kidnappers.
"If this provides them with a justification to release Jill, that would be wonderful, but we are not sure it will," Casey said. "We just want her released by any means."
Last week, the military confirmed it was holding nine Iraqi women, and it was not known when the others might be let go. Two more women were detained Wednesday for alleged insurgent activities, the military said Thursday.
Iraqis taken into custody on suspicion of insurgent activity are interrogated and investigated to determine if there is evidence to charge them. The cases are referred to a U.S.-Iraqi committee, which determines if the detainees should be released. The process can take months.