The former chief prosecutor for the International Criminal Court (ICC) is pushing for a case to be opened into the “ongoing genocide” against Iraq’s Yazidi community at the hands of ISIS militants.

Luis Moreno Ocampo said he was approached in the United States recently by Yazidi activists who are seeking justice for the systematic slaughter, rape and enslavement of thousands of members of the religious minority in northern Iraq.

“It’s a very clear case. It’s an ongoing genocide because there are still people in captivity,” Ocampo told Reuters in an interview in Erbil, capital of Iraq’s autonomous Kurdistan region, late on Wednesday.

It could take years for such a case to be brought to trial, however, given the legal, political and practical hurdles.

The ICC lacks jurisdiction over Iraq because its government is not a signatory of the treaty that established the tribunal, but it would have the right to investigate crimes committed by nationals of one of its 123 member countries.

The court, based in The Hague, has never brought a case on such grounds before and it would mean only nationals of those countries could be tried.