Francis made his remarks in his yearly speech to diplomats accredited to the Vatican, an overview of the world situation which has come to be known informally as his “state of the world” address.

Francis spoke of “the war in Ukraine, with its wake of death and destruction, with its attacks on civil infrastructures that cause lives to be lost not only from gunfire and acts of violence, but also from hunger and freezing cold”.

He then immediately quoted from a Vatican constitution, saying “every act of war directed to the indiscriminate destruction of whole cities or vast areas with their inhabitants is a crime against God and humanity which merits firm and unequivocal condemnation”.

Referring to the Cuban missile crisis in 1962, he said: “Sadly, today too, the nuclear threat is raised, and the world once more feels fear and anguish.”

He repeated his appeal for a total ban on nuclear weapons, saying even their possession for reasons of deterrence is “immoral”.

Iran’s death penalty

Meanwhile, Francis also condemned Iran for using the death penalty against demonstrators demanding greater respect for women.

The pope’s remarks were his strongest since the start of nationwide protests in Iran following the death last September of 22-year-old Kurdish Iranian woman Mahsa Amini in police custody.

“The right to life is also threatened in those places where the death penalty continues to be imposed, as is the case in these days in Iran, following the recent demonstrations demanding greater respect for the dignity of women,” Francis said.

“The death penalty cannot be employed for a purported state justice, since it does not constitute a deterrent nor render justice to victims, but only fuels the thirst for vengeance,” he said.

He then repeated an appeal for an end to the death penalty worldwide, saying it is ” always inadmissible since it attacks the inviolability and the dignity of the person”.

Four protesters have been executed in the aftermath of the unrest in Iran.