The Vatican pushed back Friday against claims that Pope Francis failed to protect two fellow Jesuit priests who were kidnapped during Argentina's military dictatorship.
The accusations have resurfaced since the Argentine cardinal's unexpected election to the papacy two days ago.
A book by investigative reporter Horacio Verbitsky accuses Francis, who was then Jorge Mario Bergoglio and was head of the country's Jesuit order, of deliberately failing to protect the two priests, Orlando Yorio and Francisco Jalics, when they were seized by the navy. They were found alive five months later.
But the Rev. Federico Lombardi, a Vatican spokesman, dismissed the claims -- which date back to Argentina's so-called Dirty War from 1976 to 1983 -- as false and defamatory.
"The campaign against Bergoglio is well-known and goes back to many years ago. It was promoted by a defamatory publication," Lombardi said at a Vatican news conference.
"This was never a concrete or credible accusation in his regard. He was questioned by an Argentinian court as someone aware of the situation but never as a defendant. He has, in documented form, denied any accusations," said Lombardi.
"Instead, there have been many declarations demonstrating how much Bergoglio did to protect many persons at the time of the military dictatorship," he said.
His role after he became bishop of Buenos Aires in asking for forgiveness for the church for not having done enough at the time of the dictatorship "is also well-known," Lombardi said.
A fellow Vatican spokesman, the Rev Thomas Rosica, said the accusations "reveal left-wing elements, anti-clerical elements that are used to attack the church. They must be firmly and clearly denied."
The Vatican has a lot of experience in dealing with negative publicity campaigns against individuals or the church, he said.
As for Francis, he said, "We have information before us that gives us every assurance of the tremendous credibility of this person."
Nonetheless, the incident led to rumors and allegations that Francis was complicit in the dictatorship's appalling atrocity -- that he didn't do enough to expose it and perhaps was even partly responsible for the priests' prolonged detention, said Jim Nicholson, a former U.S. ambassador to the Holy See.
Although the allegations against Francis have never been proved, they continue to haunt him, so much so that the human rights group Center for Legal and Social Studies in Argentina opposes Francis' selection as pope.
During the years of military dictatorship, up to 30,000 students, labor leaders, intellectuals and leftists disappeared or were held in secret jails and torture centers.
The claims against the new pope have cast a shadow over what has otherwise been widely viewed as a positive start for the new pontiff, who has embraced humility and simplicity.
As pope, he will have other tough questions to deal with. He takes the helm of a Roman Catholic Church that has been rocked in recent years by sex abuse by priests, and claims of corruption and infighting among the church hierarchy.
After the pomp and activities surrounding his election as pontiff, Francis' only public engagement Friday was a meeting with all the Catholic cardinals, who wait to see what changes he will make.
Francis expressed his gratitude to Benedict XVI, saying that during his nearly eight years as pontiff, he had "reinvigorated the church with his goodness, faith, knowledge and humility."
He had words of encouragement for the cardinals, too, as they seek to take the church forward. "Go back to your homes and continue your ministry enriched by the experience of these days," he said. "Let us never give in to pessimism, to that bitterness that the devil offers us every day."
Friday's gathering, aired on Vatican TV, gave the new pontiff a chance to catch up with the cardinals who were not eligible to vote in the conclave -- those age 80 or older. That's nearly half of all cardinals.
Remarking on the fact that many are getting on in years, he said the cardinals should pass on their experience to younger generations. "Wisdom is like a good bottle of wine, and we must give it to the young people," he said.
The pope, dressed simply in white, then exchanged a few warm words with each cardinal as they left the hall one by one.
Come Tuesday, St. Peter's Square will again bustle with the faithful, tourists and locals during the official Mass to inaugurate Francis as the bishop of Rome.