The United States on Wednesday doubled to $10 million its reward for the capture of the supremo of the Islamic State extremist movement, Secretary of State Mike Pompeo announced.

The US had already offered $5 million for Amir Mohammed Abdul Rahman al-Mawli before he was identified as the successor to Abu Bakr al-Baghdadi, who was killed by US commandos in an October raid in Syria.

Born in 1976, al-Mawli is a scholar in Islamic law who issued edicts to justify the persecution of the Yazidi minority, a campaign that the United Nations has described as genocide. The jihadists killed thousands of Yazidis, who practice an ancient religion, and abducted and enslaved thousands more women and girls as they rampaged across the Middle East.

Al-Mawli was born in the Iraqi city of Mosul to a Turkmen family, making him one of the few non-Arabs to ascend the ranks of the Islamic State group, which at its height ruled vast parts of Iraq and Syria and drew volunteers from the West.

The group's strongholds have been decimated but it has inspired grisly attacks around the world, including in Afghanistan and West Africa.