"Lord, have mercy on your people! Lord, forgiveness for such cruelty!" the leader of the world's 1.2 billion Catholics wrote in a guest book at the camp, where over a million people, mostly Jews, were murdered by the Germans occupying Poland during World War II.
Alone and on foot, the pope entered the camp through its gate inscribed with the notorious "Arbeit Macht Frei” ("Work Sets You Free") inscription.
At the so-called Wall of Death, where the Nazi Germans shot inmates, the visibly moved pontiff shook hands with and blessed a dozen survivors of the camp, some 70 km from the southern Polish city of Kraków.
Tribute to heroic Pole
Pope Francis then prayed in silence in the dimly-lit former cell of Polish Franciscan monk Father Maksymilian Kolbe.
According to historians, Friday marked exactly 75 years since Father Kolbe volunteered to die in place of another inmate, who had a wife and children.
After two weeks in a starvation cell, Father Kolbe was given a lethal injection of carbolic acid. He was canonized in 1982.
Pope Francis also lit a candle and prayed in front of a monument to victims next to the remains of the camp’s two largest gas chambers and crematoria.
The chambers are chilling reminders of Adolf Hitler’s “Final Solution”, a policy that led to the deaths of around six million Jews at the hands of the German Nazis in the 1940s.
Again, the pontiff stayed silent.
Pope Francis in June announced he would not deliver an address at Auschwitz.
'The grace of crying'
Talking to reporters, the pontiff said at the time that he wanted to go to that “place of horror” with a minimal entourage. “May the Lord give me the grace of crying,” the pope added.
Pope Francis at Auschwitz. Photo: EPA/FILIPPO MONTEFORTE
Auschwitz was part of the itinerary of Polish-born Pope John Paul II’s first pilgrimage to his homeland in 1979, and of the pilgrimage of Pope Benedict XVI in 2006.
Friday's prayers marked a sombre episode during Pope Francis's visit to Poland for World Youth Day, one of the largest international religious gatherings, an event which has been marked by enthusiasm and colourful professions of faith by young people.
Organizers predict that up to 1.5 million people from over 180 countries are likely to attend the main events - a night vigil with the pope on Saturday and an open-air mass celebrated by the pontiff on the last day, Sunday.
Launched by Pope John Paul II in the 1980s, World Youth Day has been held every two or three years in different countries.
(pk)