ROME, April 13 (Reuters) - U.S. President Donald Trump's attack on Pope Leo was "unacceptable," Italian Prime Minister Giorgia Meloni said on Monday, joining forces with politicians of all colors in springing to the pontiff's defense.

The statement represented an extremely rare public rebuke of Trump from Meloni, who has cultivated particularly close ties with the U.S. president, underscoring widespread anger in Italy over his broadside on Pope Leo.

Trump set off the furore by calling Leo "terrible" in a long tirade on Sunday. He subsequently posted an AI image depicting himself as a Jesus-like figure, sparking further outrage among Christians who saw the image as blasphemous.

Pope Leo, leader of the world’s 1.4 billion Catholics, swiftly responded, telling reporters he had "no fear" of the Trump administration and promising to continue speaking out against the U.S.-led war with Iran and in defence of migrants.

Meloni issued an initial statement backing Leo as he flew off on an ambitious four-nation visit to Africa, but made no specific mention of Trump's broadside.