Human rights lawyer Amal Clooney says she is requesting the transfer of a female member of the Islamic State extremist group to face justice for crimes against women from Iraq's Yazidi minority and American hostage Kayla Mueller, who was killed in 2015.

Clooney represents Yazidi women and girls who were held in the house of Umm Sayyaf, the wife of Islamic State financier Abu Sayyaf. She said the Yazidis were raped by IS men and Mueller by IS leader Abu Bakr Al Baghdadi.

Clooney told the U.N. Security Council on Tuesday that Umm Sayyaf "locked them in a room, instigated their beatings and put makeup on them to 'prepare' them for rape."

She did not say where Umm Sayyaf is being held.