Pope Leo XIV has called for the “disarming” of artificial intelligence, warning that unchecked development of the technology could lead to “new forms of slavery” and serious ethical risks to humanity.

The Pope made the remarks on Monday in his first encyclical, titled “Magnifica Humanitas”, which focuses on the social, moral and security implications of rapidly advancing AI systems.

Presenting the document at the Vatican alongside AI experts, Leo warned against the use of artificial intelligence in warfare, stressing that it should never be entrusted with decisions involving lethal force.

He also criticised what he described as an accelerating global “arms race” in AI development, saying the pursuit of geopolitical and commercial dominance risks concentrating power in the hands of a few.

According to the Pope, “disarming AI” does not mean rejecting technological progress, but ensuring that it does not dominate or dehumanise society.

He further warned that the benefits of AI are built on hidden human and environmental costs, including labour exploitation and environmental degradation linked to data and mineral supply chains.

The encyclical also rejected the use of traditional “just war” theory to justify modern technological warfare, stating that “no algorithm can make war morally acceptable.”

The Vatican said the document is intended to guide global ethical debate on AI development and may shape long-term Church teaching on technology and human dignity.