UNITED NATIONS - Karim Khan, head of a UN team investigating Islamic State (IS) crimes in Iraq, said Monday that there is "clear and convincing evidence" that the terrorist group committed genocide against the Yazidi people.

"I'm able to announce that, based upon independent and impartial investigations, complying with international standards and UN best practice, there is clear and convincing evidence that the crimes against the Yazidi people clearly constituted genocide," Khan told the Security Council in a briefing.

"More particularly, we have identified specific perpetrators that clearly have responsibility for the crime of genocide against the Yazidi community," he said.

The intent of the IS to destroy the Yazidi -- physically and biologically -- was manifest in the ultimatum that was repeated in so many different villages in Iraq: to convert or to die, said Khan, who heads the the UN Investigative Team to Promote Accountability for Crimes Committed by Da'esh/Islamic State (UNITAD).

Thousands of men, women and children were killed brutally pursuant to this ultimatum, he said.

A full scope of criminality is displayed in the awful crimes committed by the IS against the Yazidi community: executions, slavery, sexual slavery, and crimes against children, he said.

These crimes have not ended with the end of the territorial control by the IS in Iraq. Thousands of Yazidis remain missing. There is clear evidence that some children may still be detained by the IS in the region, he said.

The UN investigative team has also been able to prioritize and come to findings regarding the June 2014 massacre of predominantly Shiite unarmed cadets and other personnel at the Tikrit Air Academy, also known as Camp Speicher, said Khan.

"They were led away. Many were massacred and executed. And there is clear and convincing evidence that a variety of crimes have been committed against them: war crimes, of course, cruel treatment, murder, outrages on personal dignity."

A video deliberately put together by the IS in July 2015 clearly shows that the crime of direct and public incitement to commit genocide occurred, he said.

The UN investigative team has had language experts to analyze the video, he said. But one does not even need to look into its content to realize the incitement to genocide. The title of the video tells it all: Kill them wherever you find them.