The brutal persecution of Christians in the Middle East must be acknowledged as genocide, the European Syriac Union said today, on the first ever international day to commemorate the victims of genocide.

"It is our moral and historical duty" to acknowledge that "Chaldean-Syriac-Assyrian people face another genocide in the Middle East and existential threat," a statement from the ESU said.

"Commemoration of Victims of Genocides and Crimes against Humanity is [an] essential responsibility to the humanity and international community. Commemoration [of] past atrocities around the world is [a] strong sign of remembrance of the victims and solidarity with the current threatened groups, ethnic and religious communities."

The US Commission on International Religious Freedom on Monday called for groups systematically persecuted by Islamic State in Iraq and Syria – Christians, Yazidis, Shi'as, Turkmen and Shabaks – to be recognised as victims of genocide.

"The hallmark of genocide is the intent to destroy a national, racial, ethnic, or religious group, in whole or in part," said USCIRF chairman Robert George.

"ISIL's intent to destroy religious groups that do not subscribe to its extremist ideology in the areas in Iraq and Syria that it controls, or seeks to control, is evident in, not only its barbarous acts, but also its own propaganda."

The population of Christians in the Middle East has fallen "in an incessant way" over recent years, the ESU said.

The fall of Mosul, once considered the heartland of Iraq's Christian population, and the occupation of the Ninevah plains by ISIS has led to a mass exodus of Chaldean, Syriac and Assyrian people, the union added. They face "annihilation and destruction" under ISIS, it said.

The UN this year established 9 December as the International Day of Commemoration and Dignity of the Victims of the Crime of Genocide and of the Prevention of this Crime.

It is the anniversary of the adoption of the 1948 Genocide Convention.

In a statement to Christian Today, spokesman for the ESU David Vergili said: "Christians face another genocide with a non state actor which aggravate and complex the situation. In this regards, the rapid action by the international community is vital in order to stop metastasising of the harm inflicted in these ancient communities.

"Survival and existence of Christians in Middle East is fundamental for the future as they had been a bridge between Occident and Orient in the history."