The Vatican is urging Muslim leaders to denounce the "barbarity" of the Islamic State's attacks against Christians and other minorities in Iraq, saying their credibility is on the line, the Associated Press reports.

The Vatican's Pontifical Council for Interreligious Dialogue, the main Vatican office that deals with the Muslim world, said Tuesday, Aug 12, that the forced expulsions and massacres of Christians and minority Yazidis shamed humanity and couldn't be justified by any religion.

The office said the "unspeakable criminal acts" — the beheading, crucifying and hanging of bodies in public places, the "barbaric practice of infibulation," the abduction of women and girls as spoils of war, and the destruction of Christian religious symbols — required a "clear and courageous stance on the part of religious leaders, especially Muslims."

"If not, what credibility will religions, their followers and their leaders have?" the statement warned.

Pope Francis has stepped up his denunciation of the attacks against Christians. He has also sent a personal envoy, Cardinal Fernando Filoni, to the region to show solidarity with the victims, provide them with emergency funding and meet with Iraqi and Kurdish leaders. The Fides missionary news agency said Filoni was heading to Iraq via Jordan on Tuesday.