Steinmeier said Hannelore Krause, who is married to an Iraqi doctor, had been released on Tuesday afternoon. But he said that her son, Sinan, who was also abducted, remains in captivity.

"As relieved as we are about Hannelore Krause's release, uncertainty remains about the fate of her son," Steinmeier said on Wednesday. He said the German government was doing everything it could to ensure that Sinan Krause, too, would be freed.

Hannelore and Sinan Krause were abducted in Baghdad on Feb. 6 by a group called Kataeb Siham al-Haq (Righteous Arrows Battalions). The kidnappers had insisted that Germany withdraw its peacekeeping troops from Afghanistan and threatened to kill the hostages, if their demands were not met.

There was no immediate word on the details of how Krause came to be released. The German government's official policy is that it does not pay ransom to free kidnapped German citizens.