The statement made by Pope Francis last week that Christians should not think of "building walls"—just like what Donald Trump says he intends to do in case he wins the White House this November—might have backfired him.

This is because, according to WND, the pope's sovereign city-state, Vatican City, is surrounded by giant walls. Moreover, the walls were specifically built by a Pope Francis predecessor to repel Muslim invaders.

Historical records show that in 846, Muslim raiders known as the Saracens looted Old St. Peter's Basilica and the Papal Basilica of St. Paul outside the walls, taking priceless treasures from the shrines.

Stunned by the Muslim attack on Christendom, Pope Leo IV created the Leonine Wall, completely surrounding the Vatican Hill. Additional defences were added in the 15th and 16th centuries.

On Friday, the Vatican tried to defuse the controversy sparked by the pope's remarks. Vatican spokesman Fr. Federico Lombardi said the pope's statements about building bridges and not walls were in "no way ... a personal attack [on Trump] nor an indication of how to vote."

However, Dr. G.M. Davis, the author of "House of War: Islam's Jihad Against the World," said the Vatican statement may not be enough to repair the damage to the pope's reputation.

"The thinly veiled attack on Trump and the implication Trump is no Christian seems little more than a cheap political shot unworthy of a spiritual leader of global reach," Davis told WND.

"Had Trump been Catholic, it would have amounted to a back-handed excommunication. Whatever Pope Francis' intent, he only diminished himself and came across more as a competing presidential candidate than the leader of the world's largest Christian organisation," Davis said.

Davis also blasted the mainstream media for their "almost intentional stupidity" in misinterpreting Trump's call for a wall to mean no one is going to be admitted to the United States.

"Obviously what Trump meant was to get a much better handle on regulating our southern border, with 'walls' but also doors, gates, fences and more border security," Davis said.

"Indeed, Trump could have pointed to the Vatican itself as a model of border security: massive, impenetrable walls accompanied by efficient security, gates, metal detectors, etc., which allow countless numbers of people to come and go in a safe manner."