Around 100 German Muslims have gathered in the southern city of Offenbach, near Frankfurt, to call for the release of a German woman taken hostage in Iraq. Organisers said Saturday’s show of solidarity was meant to send a signal that violence is incompatible with Islam. It comes amid rising concerns over the fate of archaeologist Susanna Osthoff, who was seized along with her driver just over a week ago.Some German media are reporting that a deadline given by her kidnappers in a video has already passed. Germany’s foreign ministry says it’s still heard nothing from her captors, who said Osthoff would be killed unless Germany withdrew all support for the Iraqi government. Meanwhile time is running out for four more Western hostages being held in Iraq, seen in a video broadcast on an Arabic news channel. One Briton was among the captives taken last week, along with two Canadians and an American. The militants holding the aid workers have threatened to kill them unless Iraqi prisoners are released from detention centres by December 8.