Iraq is not capable of trying atrocities committed by Islamic State during the battle for Mosul so it must find other routes to justice such as the International Criminal Court (ICC), a U.N. human rights report said on Thursday.

At least 2,521 civilians were killed during the nine-month battle, including 741 people who were executed, the report said. Most died as a result of Islamic State (ISIL) attacks.

It cited testimonies of mass abductions by Islamic State, as well as killings, the use of human shields, and deliberate targeting of civilians and their homes.