"The Karkh criminal court in Baghdad sentenced to death by hanging one of the most prominent leaders of IS, who served as a deputy of Baghdadi," judicial spokesman Abdel Sattar Bayraqdar said.

Ismail Alwan Salman al-Ithawi was extradited from Turkey earlier this year having fled Syria as the group's self-proclaimed "caliphate" crumbled.

He was tracked and detained through cooperation between Turkish, Iraqi and US intelligence agencies, a senior Iraqi official told AFP in February.

A native of the Iraqi city of Ramadi, Ithawi was accused of holding several positions including IS "minister" in charge of religious edicts.

Iraq declared "victory" over IS In December after a three-year war against the jihadists who once controlled nearly one third of the country as well as swathes of neighbouring Syria.

Baghdadi has been pronounced dead on several occasions, but an Iraqi intelligence official said in May that he remained alive in Syrian territory by the Iraqi border.

The IS chief called on Muslims to wage "jihad" in a purported new audio recording released last month.