"The kidnapping has nothing to do with the nature of our religion and also finds no justification in the Koran," the chairman of the Islamic Council for Germany, Ali Kizilkaya, told the newspaper Bild am Sonntag.

"I call on the kidnappers in the name of humanity: Let the innocent hostages go immediately."

Hannelore Krause, who is 61 and married to an Iraqi doctor, and their 20-year-old son Sinan, who works at the Iraqi foreign ministry, were seized on February 6.

Previous appeals

Sunday's appeal came after Krause's husband and Sinan's wife made an emotional plea for their release in a video message broadcast on channels in Germany and the Arab world Friday.

German President Horst Köhler last week also called for their release in a video broadcast.

Earlier this month, a militant Islamist group in Iraq called the Kataeb Siham al-Haq (Righteous Arrows Battalions) threatened to execute the hostages unless Germany pulls its troops out of Afghanistan.

Germany has nearly 3,000 troops in northern Afghanistan, where it commands the NATO-led International Security Assistance Force.

No bowing to threats

Germany's interior minister, Wolfgang Schäuble, reaffirmed that despite the threats to kill the hostages, Germany would not let itself be blackmailed by terrorists.

In an interview broadcast on German public radio, Schäuble said militant Islamists are trying to influence the behavior of free societies.

"And we must be clear in telling them they will not achieve that goal," he said.