TURIN, Italy - Pope Francis has denounced what he calls the "great powers" of the world for failing to act when there was intelligence indicating Jews, Christians, homosexuals and others were being transported to death camps in Europe during World War II.

He also decried "how many Christians suffered" and died in gulags later in Russia under the Stalin dictatorship.

The pope's harsh assessments came in impromptu remarks during his visit to Turin, northern Italy, when he told young people he understands how they find it hard to trust the world.

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Francis said: "The great powers, they divided Europe like a cake" in the 1930s and 1940s and lamented that in today's world "everything is done for money."

He also lamented the hypocrisy of those advocating peace while also manufacturing or selling arms.

Earlier Sunday, the pontiff paused in silent prayer before the Shroud of Turin, becoming the latest of hundreds of thousands of people who have come this year to Turin's cathedral to view the burial linen some believe covered the body of Jesus after crucifixion.

Francis sat for several minutes before the shroud, contained in a protective glass case. He lowered his head at times in apparent reflection and occasionally gazed up at the 14-foot long cloth. Then he took a few steps, placed his hand on the case, and walked away without comment.

Pope Francis touches the holy Shroud, believed by some Christians to be the burial shroud of Jesus of Nazareth, on June 21, 2015 in Turin's cathedral. ALBERTO PIZZOLI/AFP/Getty Images

Later, after celebrating Mass for faithful in a packed Turin square, Francis gave his impression of the cloth as he spoke of the love Jesus had for humanity when being crucified.

"Icon of this love is the Shroud, that, even this time, has attracted so many people here to Turin," Francis said. "The Shroud draws (people) to the tormented face and body of Jesus and, at the same time, directs (people) toward the face of every suffering and unjustly persecuted person," the pope said.

The shroud's display began April 19 and runs through June 24.

Other pontiffs have made the journey to the northern city during previous displays of the shroud. When John Paul II saw the shroud in 1998, he said the mystery surrounding the cloth forces questions about faith and science and whether it really was Jesus' burial linen. He urged continuous study. Benedict XVI described the cloth as an icon "written with the blood" of a crucified man.

Skeptics say the cloth bearing the image of a crucified man is a medieval forgery.

Turin, the heartland of Italy's auto industry, is considered Italy's blue-collar labor capital, and Francis used his two-day visit to the city to denounce exploitation of workers, singling out women, young people and immigrants as frequent victims.

"Immigration increases competition, but migrants shouldn't be blamed because they themselves are victims of the injustice, of this throw-away economy and of wars," Francis said in a speech in a square outside the cathedral.

He then made an apparent reference to European countries as well as some northern Italian regions which are refusing or reluctant to take some of the tens of thousands of migrants who have landed at southern Italian ports after being rescued in the Mediterranean from overcrowded, unseaworthy smugglers' boats.

"It makes one cry to see the spectacle of these days in which human beings are treated as commercial goods," Francis said.

Turin is the Piedmont region's capital, and during Mass, the Argentine-born Francis quoted from a poem in local dialect that praises the qualities of those who emigrated from Piedmont - like some of his own ancestors - to seek work abroad.

"Our ancestors knew well what it meant to be rock-solid," Francis said. Quoting from the poem, the pope said these emigrants were "Proper and sincere, they appear to be what they are .... they speak little but they know what they are talking about, even if they walk with ease, they go far. They are people who don't spare time and sweat -- our free and stubborn race."

On Monday, before he heads back to Rome, Francis will lunch in Turin with some of his relatives who live in Piedmont.