ROME — While serving as the archbishop of Buenos Aires in 2009, the future Pope Francis once wore a bulletproof vest at the insistence of Argentina’s government, according to documents released by an Argentine news site Saturday.

According to court documents, the government request to then-Cardinal Jorge Mario Bergoglio to take additional security precautions came in response to anonymous reports that a local union leader was planning the prelate’s assassination.

A former Bergoglio aide told Crux that the future pope wore the vest only once and decided not to use it again.

That union leader, Luis D’Elia, was also known as a strong supporter of the center-left government of Argentine President Cristina Fernández de Kirchner.

The e-mail about the plot, sent from an anonymous user account, claimed that “an attempt will be made against the life of Cardinal Bergoglio, and the men in charge of doing so are members of D’Elia’s inner circle.”

The message also said that the “imminent” assassination would be a “present for the president’s Christmas tree,” a reference to the fact that Kirchner and Bergoglio had a notoriously rocky relationship.

According to the court documents, a government official forwarded the e-mail to the chief of the Federal Police Department, who decided that Bergoglio was to be placed under protection, against his will if necessary.

Also according to the report, the cardinal was also forced to use a bulletproof vest.

Federico Wals, who worked closely with Bergoglio for several years as spokesman for the Buenos Aires archdiocese, confirmed the threat to Crux.

He also recalled the cardinal’s opinion of the vest: “He complained about it being uncomfortable after using it once, and decided not to use it again,” he said.

According to Wals, the prelate’s reluctance was also based on his trust in God’s protection.

“It’s just as he does now every time, he accepts a maté from someone,” Wals said, referring to a tea popular in Argentina that people in crowds often hand to Francis during his public appearances.

The alleged threat against Bergoglio was archived in February 2010, when a police investigation against D’Elia determined that there was no foundation for it.

Although the Latin American pope has been a constant headache for his personal guard, reports over recent threats against Pope Francis’ life have been repeatedly dismissed by the Vatican spokesman.

Before the pontiff’s September one-day trip to Albania, a Muslim-majority nation, Italian journals reported that Francis was a target of the terrorist group ISIS.

At the time, Lombardi said: “There is no particular reason for concern. Of course we are all worried over news about ISIS and the situation in the Middle East, but there are no risks or specific threats.”

Lombardi’s low-key approach reflects the Vatican’s overall handling of Francis’ security on trips outside the Vatican. Over the summer, the Vatican also downplayed concerns that Francis might be a target for organized crime bosses during one-day trips to the heart of Italy’s Mafia country.