UNITED NATIONS (Reuters) - International human rights lawyer Amal Clooney and a young Yazidi woman who was enslaved and raped by Islamic State fighters pushed Iraq on Thursday to allow a United Nations investigation into crimes by the militant group.

Britain is drafting a United Nations Security Council resolution to establish a U.N. investigation, but Clooney said the Iraqi government needs to send a letter formally requesting the inquiry before the 15-member council can vote.

Islamic State is committing genocide against the Yazidis in Syria and Iraq to destroy the minority religious community through killings, sexual slavery and other crimes, U.N. experts reported in June last year.

Clooney, who represents Nadia Murad and other Yazidi victims of Islamic State, said that despite public support by Iraq for a U.N. investigation, the government has not yet made a request.

“We do want to see an investigation take place with the cooperation of the Iraqi authorities,” Clooney told Reuters in an interview after speaking at a United Nations event on accountability for crimes committed by Islamic State.

“But ultimately if that support is not forthcoming in terms of real action, then the U.N. has to think of other ways in which to achieve accountability,” she said.

The Yazidis are a religious sect whose beliefs combine elements of several ancient Middle Eastern religions. Islamic State militants consider the Yazidis to be devil-worshippers.

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Clooney said the Security Council could establish an inquiry without Iraq’s consent, the 193-member U.N. General Assembly could establish a special team to preserve evidence and prepare cases - as it did for Syria in December - or the Security Council could refer the case to the International Criminal Court.

“All these options are on the table. They must be seriously considered, because victims like Nadia can’t expect to wait forever,” said Clooney, adding that it was extremely important that evidence was preserved for future prosecution.

When asked what may be preventing Iraq from requesting the investigation, Murad, 23, speaking through a translator, said: “They think that all Iraqis are persecuted by Daesh and they have to seek justice for everybody.”

Daesh is another name for Islamic State.

“We will be seeking help and assistance,” Iraq’s U.N. ambassador, Mohamed Ali Alhakim, told the U.N. event where Murad also spoke. He did not immediately respond to a request for comment on why Iraq had not yet requested a U.N. inquiry.

Britain’s U.N. ambassador, Matthew Rycroft, told the U.N. event that he was working with Iraq on the issue.

“The proposal should support Iraq’s national efforts and fully respect it national laws and sovereignty. But it is also an urgent task. And we look forward to finalizing that proposal with you very, very soon,” he said.

Murad was abducted and held by Islamic State fighters for three months in 2014 in Mosul. She told her story to the U.N. Security Council in December 2015 and since then has been campaigning for justice.

An exhausted Murad told U.N. ambassadors on Thursday: “My words, tears and my testimony have not made you act. I wonder whether there is any point in continuing my campaign at all.”