A German woman and her driver are believed to have been kidnapped in Iraq, and Berlin has set up a special team to secure her safe return.
A picture believed to show Osthoff and her driver, issued by ARD TV
Chancellor Angela Merkel has said: "According to current information we have to assume it is a kidnapping."
German TV station ARD says it has a video showing the woman and her driver, with kidnappers demanding Germany cut ties with the Iraqi government.
The woman, Susanne Osthoff, has apparently been missing since Friday.
Her driver is also believed to have been kidnapped.
Ms Osthoff, an archaeologist, is a fluent Arabic speaker who is married to an Iraqi and has also been involved in aid work.
Germany does not have troops in Iraq and former Chancellor Gerhard Schroeder's refusal to back the war weakened ties between Germany and the US.
Ms Merkel says she wants to improve relations with Washington but has ruled out sending troops to Iraq.
German Foreign Minister Frank-Walter Steinmeier is visiting the US and is scheduled to meet Secretary of State Condoleezza Rice on Tuesday.
"The German government sharply condemns the act and urgently appeals to the perpetrators to return both safely and without delay," Ms Merkel said.
She added that the German Foreign Ministry has set up a crisis team to help in securing the release of the hostages.
"The German government will do everything in its power to bring both back to safety," she said.
In a separate incident, four Western aid workers were seized in Baghdad on Saturday.
The hostages include two Canadians and a British man, Professor Norman Kember. The fourth is believed to be an American.
It is estimated that at least 200 foreigners have been abducted in Iraq over the last 18 months. Some have been executed by their kidnappers.