A senior bishop in Vatican City has criticised the Pope for mentioning the devil too many times during his homilies.

The cleric, who spoke on condition of anonymity, told the Washington Post that Pope Francis "never stops" speaking about Satan.

"It's constant," the bishop said. "Had Pope Benedict done this, the media would have clobbered him."

His criticism found an echo. According to journalist Sara Lin Wilde, "Francis loves to bring up Satan".

"It seems like the Church is heading to a very conservative historical moment with Pope Francis at the helm," Wilde wrote on patheos.com.

Journalist Anthoni Faiola said: "After little more than a year atop the throne of St Peter, Francis's teachings on Satan are already regarded as the most old school of any pope since at least Paul VI."

"He is opening the door to superstition," said Vito Mancuso, a Catholic theologian and writer.

By focusing on old-school interpretations of the Devil, some progressive theologians said the Pope was undermining his reputation of a modern leader.

Francis, who took the papacy in March 2013 and spoke about the Devil in his very first homily , defended himself by saying that people should always be aware of the Devil's presence in the modern world.

"Look out because the Devil is present," he said during a Mass at the Vatican's chapel in St Martha's House in April. "When we prefer to gossip, gossip about others, criticise others - these are everyday things that happen to everyone, including me – these are the temptations of the evil one who does not want the Spirit to come to us and bring about peace and meekness in the Christian community."

Vatican officials said had witnessed an increase in mystical rites in the Church, including exorcism.

During the ninth convention on exorcism, almost 200 delegates - mainly priests and nuns from all over the world - said satanic cults were spreading on the internet.

The new pope, exorcists said, had become their champion in the face of modern sceptics, many of them within the Catholic faith.