The little-known Iraqi Islamist group, Kataeb Siham al-Haq or the Arrows of Righteousness Group said in a videotape posted on Saturday on an Islamist website: "We give the German government 10 days from the date of this statement to announce and start the withdrawal of its troops from Afghanistan."

"We have warned them. Otherwise, you will not even see one corpse for these two agents," said one of three masked gunmen who appeared to be standing behind the purported hostages.

"Those people aren't joking"

The footage showed Hannelore Marianne Krause, 61 urging the German government to help her. It also showed Krause's passport.

Krause wearing a blue headscarf was shown crying along with her dark-haired bearded son who sat on the floor next to her while she made a lengthy appeal in German.

A written Arabic translation of her statement said that she was calling on German Chancellor Angela Merkel to save her life and that of her son by pulling out troops from Afghanistan.

"I have been held captive for a long time. I beg you to help me. I was very happy when you became chancellor but unfortunately until now you did not help me," the translation said.

"I am under threat. These people want to kill my son in front of me and then kill me if German troops do not withdraw from

Afghanistan," the translation said. "Please implement my demands. Those people are not joking."

She also asked German organizations to apply pressure on Berlin to meet the kidnappers' demands.

In Berlin, the German foreign ministry said a crisis team was studying the situation.

Germany a vocal opponent of the Iraq war

Foreign Minister Frank-Walter Steinmeier confirmed on February 12 that two German citizens had been missing in Iraq for a week and might have been abducted.

The Berlin daily Tagesspiegel, citing security sources, reported at the time that the victims were a woman in her 60s, who is married to a Iraqi doctor, and their son who is in his 20s.

It is the third abduction of Germans in Iraq since the US-led war was launched in 2003.

According to the German Foreign Ministry there are still about a hundred German nationals in Iraq, people working for German and international companies or diplomatic services. Germany has issued a security warning on travel to Iraq due to the unstable security environment there.

About a year ago, two German technicians, Rene Bräunlich and Thomas Nitzschke were released by their kidnappers after a three-month hostage ordeal. And in November 2005 Susanne Osthoff, a German archeologist working for an aid organization, was released after the German government was reported to have paid a ransom to the tune of several million euros. Berlin however denies it.

Germany vehemently opposed the US-led war in Iraq, but it does have 3,000 troops in the relatively stable north of Afghanistan, where it commands the International Security Assistance Force (ISAF).