Pope Leo XIV has said that the world is being “ravaged by a handful of tyrants” who spend billions on war, in comments that will be seen as another sharp escalation in his almost week-long feud with the White House over the US-Israel war on Iran.

The first American-born pontiff did not mention Donald Trump by name, but used his speech in Cameroon on Thursday to denounce world leaders that invoke religion to justify violence against other nations.

His comments came as US bishops offered their full-throated support to the head of the Catholic church, who has been under fire from Trump for days after speaking out against the Iran war.

“Woe to those who manipulate religion and the very name of God for their own military, economic and political gain, dragging that which is sacred into darkness and filth,” Leo told a gathering at Saint Joseph Cathedral in the western city of Bamenda.

“They turn a blind eye to the fact that billions of dollars are spent on killing and devastation, yet the resources needed for healing, education and restoration are nowhere to be found.

“The world is being ravaged by a handful of tyrants, yet it is held together by a multitude of supportive brothers and sisters,” said the pontiff, who is on an 11-day tour of Africa.

The unusually forceful statement from the US Conference of Catholic Bishops, meanwhile, came after JD Vance, Trump’s vice-president and a converted Catholic, assailed Leo for speaking out against the war, in effect telling the pope to stay out of politics and “stick to matters of morality”.

On Tuesday, Vance questioned Leo’s call for peace by challenging his benchmark for a “morally justifiable” war. “When the pope says that God is never on the side of people who wield the sword, there is more than a 1,000-year tradition of just war theory,” he told a Turning Point USA event at the University of Georgia.

But the bishops said Vance had mis-stated Leo’s position. “For over a thousand years, the Catholic Church has taught just war theory and it is that long tradition the Holy Father carefully references in his comments on war,” said the statement on Wednesday, attributed to James Massa, chair conference’s committee on doctrine.

“A constant tenet of that thousand-year tradition is a nation can only legitimately take up the sword ‘in self-defense, once all peace efforts have failed’. That is, to be a just war it must be a defense against another who actively wages war, which is what the Holy Father actually said: ‘He does not listen to the prayers of those who wage war.’

“When Pope Leo XIV speaks as supreme pastor of the universal Church, he is not merely offering opinions on theology, he is preaching the Gospel and exercising his ministry as the Vicar of Christ.”

Leo told reporters earlier this week on a plane to Algeria at the start of his trip that he did not fear Trump.

“I do not see my role as that of a politician. I am not a politician and I do not want to enter a debate with him,” he said.

“I continue to speak strongly against war, seeking to promote peace, dialogue and multilateralism among states to find solutions to problems.”

Trump posted an image to his Truth Social platform on Wednesday depicting himself being embraced by Jesus with the US flag as a backdrop, days after a backlash from supporters – including many on the religious right – forced him to delete an AI-generated image portraying the robed president as a Christ-like healer of the sick.

In a separate development, the Miami Herald reported on Wednesday that the Trump administration, in an apparent act of retaliation, was ending funding for a Catholic church-based charity in the city that shelters immigrant children.

Catholic Charities of the Archdiocese of Miami said the White House had pulled a longstanding $11m contract from the Office of Refugee Resettlement (ORR) for a program that provides specialized services for unaccompanied and undocumented minors who have been detained by Immigration and Customs Enforcement (ICE).

“The US government has abruptly decided to end more than 60 years of relationship … and [the services] will be forced to shut down within three months,” Thomas Wenski, the archbishop of Miami, said in a statement to the newspaper.

“[The] services for unaccompanied minors have been recognized for their excellence and have served as a model for other agencies throughout the country. Our track record in serving this vulnerable population is unmatched.”

Emily Hilliard, a spokesperson for the federal health and human services department, told the Herald that the average daily population of unaccompanied migrant children in the agency’s care during Trump’s second term of office was about 1,900 and “significantly lower” than it was under the Biden administration.

“ORR is closing and consolidating unused facilities as the Trump administration continues efforts to stop illegal entry and the smuggling and trafficking of unaccompanied alien children,” Hilliard said in a statement that did not specifically mention the program run by the archdiocese of Miami.

Wenski told the Herald he accepted some initiatives would be scaled back as migration declined, but said it was “baffling that the government would shut down a program that it would be hard-pressed to replicate at the level of competence” of the church.