Hadya Abdel Qader had been held without charge since her arrest by Iraqi security forces in Mosul, in a part of the northern city held by IS.

The jihadist group was ousted from Mosul in July last year after a months-long battle, during which suspected members of the jihadist group were rounded up.

But a judge at Baghdad's central criminal court found no evidence to link Qader to IS, a judicial source said Wednesday.

The 40-year-old will remain in prison while prosecutors are given a month to decide whether to confirm or overturn the judge's ruling.

The office of Germany's anti-terrorism prosecutor did not confirm the details of the case, telling AFP only that her name "was not unknown" to authorities.

Iraq has sentenced more than 300 people to death for belonging to IS, including around 100 foreigners. At least the same number have received life terms, Iraqi judicial sources have said.

In April, an Iraqi court commuted the death sentence of a German woman of Moroccan origin, reducing her sentence for IS membership to a 20-year life term.

A 17-year-old German girl was sentenced in February to six years in prison for IS membership and illegally crossing the border.