BAGHDAD -- An influential Sunni clerical group called yesterday for the release of five Westerners taken hostage in a grim revival of the kidnappings that shook Iraq last year, saying they should be freed on humanitarian grounds.
The Association of Muslim Scholars is believed to have contacts with some Sunni insurgent groups and has helped mediate the releases of other captives in Iraq.
The five include four aid workers from the group Christian Peacemaker Teams -- Tom Fox, 54, of Clearbrook, Va.; Norman Kember, 74, of London; and James Loney, 41, and Harmeet Singh Sooden, 32, of Canada -- and German archeologist Susanne Osthoff, 43.
The association said freeing Osthoff would recognize Germany's ''positive" stand toward Iraq. Germany strongly opposed the US-led invasion in 2003.
Osthoff and her Iraqi driver were seized Friday and were later pictured in a videotape blindfolded on a floor, with militants armed with a rocket-propelled grenade standing beside them.
In the northern city of Mosul, the head of the regional antiquities department, Muzahem Mahmoud al-Zawbai, said he warned authorities Osthoff was not safe and that he could not be responsible for her security due to insurgent activity. It was unclear if the authorities relayed the warning to Osthoff, who was working to renovate an historic house.
Stephan Kroll, an archeologist at Munich's Ludwig-Maximilian University, where Osthoff studied, said she had told colleagues she was worried ''something could happen to her."
Osthoff said she had been ''stopped and held" on several occasions by unidentified groups seeking money,
Kroll said Osthoff left the institute in 1991 without completing her master's degree and had ''very limited expertise" as an archeologist. He said he doubted reports that antiquities smugglers could have kidnapped her because she was disturbing their work.
University staff and friends pleaded with Osthoff not to go back to Iraq, but ''she never listened. She went her own way," Kroll said. ''She thought it was her mission to help the people."
The statement from the Muslim clerics said Osthoff was married to an Iraqi Muslim, ''who is a member of the Shammar tribe from Mosul." The tribe, one of Iraq's largest, includes Shiites as well as Sunni clans. Vice President Ghazi al-Yawer is a senior Shammar figure.
The kidnappers have threatened to kill Osthoff and her driver unless Germany halts contacts with the Iraqi government. German Chancellor Angela Merkel vowed in a speech before parliament yesterday that her government would ''not let ourselves be blackmailed" by militants.
A report on Germany's ZDF television said there were indications the kidnappers were Sunnis linked to the former ruling Baath party.
The four Christian aid workers were taken captive Saturday and appeared in a video broadcast Tuesday by Al-Jazeera television.