Pope Francis has denounced the "snake tactics" of those who spread fake news, saying the first case of misinformation is in the Bible when Eve is tempted by the serpent to eat the forbidden fruit.
The episode showed the "dire consequences" that fake news can have, the Pope warned in a document.
Pope Francis also said it led only to the spread of arrogance and hatred.
Social media users and journalists should unmask manipulative tactics that foment division, he said.
The document The Truth Will Set You Free - Fake News and Journalism for Peace was issued ahead of the Catholic Church's World Communications Day on 13 May, and it was the first time the Pope has written on the topic.
It comes amid a debate on ways to contain the spread of fake news on social media platforms and how it may have influenced recent elections, including in the US in 2016.
"Spreading fake news can serve to advance specific goals, influence political decisions, and serve economic interests," the Pope said.
Comparing it to the serpent's message of temptation in the Bible, he said: "We need to unmask what could be called the 'snake tactics' used by those who disguise themselves in order to strike at any time and place."
He called for "education for truth" that would teach people how to discern, evaluate and understand information.
Additionally, he said the role of journalists - whom he called "the protectors of news" - was "not just a job, it is a mission".
They should focus less on breaking news and more on "exploring the underlying causes of conflicts", he said.