WATCH: Pope Leo XIV calls Trump's Iran threat 'truly unacceptable'

Pope Leo XIV said Tuesday that President Donald Trump's threat to Iran that he would wipe out an entire civilization was "truly unacceptable."

Watch the pope's comments in the video player above.

"There are certainly issues of international law here, but even more so a moral issue for the good of the whole, entire population," the pope said in Italian to reporters outside his residence in Castel Gandolfo, Italy. "I would like to invite everyone to truly think in their hearts about the many innocent people, so many children, so many elderly, completely innocent, who would also become victims of this escalation of a war that began from the very first days."

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Leo was responding to Trump's threat earlier in the day that, if Iran's leaders did not agree to a deal that would open the Strait of Hormuz, "a whole civilization will die tonight, never to be brought back again." Trump has imposed an 8 p.m. Eastern deadline for Iranian leaders. The president has also said the U.S. has a "plan" to target Iran's power plants and bridges — actions that experts say could constitute a war crime.

The leader of the Catholic Church called on "all people of goodwill to search, always, for peace and not violence, to reject war." He referred to the monthlong conflict with Iran as "an unjust war" that is "not resolving anything."

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The leader of Catholic bishops in the United States echoed the pope in a statement. "The threat of destroying a whole civilization and the intentional targeting of civilian infrastructure cannot be morally justified. There are other ways to resolve conflict between peoples," Archbishop Paul Coakley said. "I call on President Trump to step back from the precipice of war and negotiate a just settlement for the sake of peace and before more lives are lost."