“Sexual pleasure is a gift from God” but Catholics must avoid pornography, Pope Francis has said.

The pontiff made the remarks during a catechesis devoted to the “vice of lust” at his general audience in Saint Peter’s Square on Wednesday.

Sexual pleasure was something to be cherished, he said, but it was being “undermined by pornography”, and “satisfaction without a relationship can generate forms of addiction”.

“We must defend love,” the pope said. But he added: “Winning against the battle of lust can be a lifelong undertaking.”

Francis appeared to be responding to his conservative critics, who were incensed last week after a book resurfaced featuring sexually explicit content written decades ago by the Vatican’s head of doctrine.

The book, now out of print, by Víctor Manuel Fernández, an Argentinian cardinal close to Francis who was already known as the author of another sexually charged book written in his youth, included a chapter describing the differences between male and female orgasms.

In response to the more recent scandal, Fernández, whose appointment to one of the Vatican’s most powerful positions was criticised by conservative cardinals, told Crux: “I would certainly not write [that] now.”

In 2022, during a talk with seminarians about the dangers of social media, the pope warned against the “devil” of digital pornography, while admitting that priests and nuns also watch online porn. “It is a vice that so many people have. So many laymen, so many laywomen, and also priests and nuns,” he said. “The devil enters from there.”

In late 2020, the Vatican was left in an embarrassing predicament when it was forced to “seek explanations from Instagram” after Pope Francis’s official Instagram, which along with his other social media accounts is managed by a team of people, “liked” a photo of the Brazilian model Natalia Garibotto. The “like” from the pope’s account was visible on Garibotto’s page for several days before being unliked.

The Vatican said at the time: “We can exclude that the ‘like’ came from the Holy See”.