PHILADELPHIA (AFP) - Pope Francis on Sunday visited the largest prison in Philadelphia, shaking the hands of 100 inmates and offering them words of comfort in a speech focused on hope and rehabilitation.
It was a visit that shone a spotlight on America's broken prison system, home to around 2.2 million inmates - the largest prison population among developed nations in the world.
US President Barack Obama wants to cut the number of people incarcerated and curb use of solitary confinement and end mandatory minimum sentences.
The pope's visit to the Curran-Fromhold Correctional Facility was one of the last stops on his packed, six-day tour of the United States.
He sat on a wooden chair, especially crafted for him by inmates, and told prisoners that their incarceration could have only one purpose: rehabilitation and paving their return to society.
"All us are invited to encourage, help your rehabilitation," he said. "All of us have something we need to be cleansed of, or purified from. All of us."
It is during meetings with the disadvantaged that Francis has appeared most at ease on his punishing schedule, where he has been greeted by adoring crowds in Washington, New York and Philadelphia.
He finished his short speech with a blessing and a simple "thank you", then walked down the lines of carefully selected inmates, who were seated in blue prison scrubs.
He shook their hands and offered private words of comfort to each.
"The chair is beautiful. Thank you very much for the hard work," he said to applause, giving them a little wave goodbye.
The pope is a vocal opponent of indefinite solitary confinement and used an historic address to Congress to urge American politicians to abolish the death penalty.
Prison visits are a central tenet of the 78-year-old Argentine's ministry and he frequently tours jails in both Italy and on overseas trips.
Shortly after his election as pope, Francis made international headlines by washing the feet of juvenile prisoners in Rome on Holy Thursday.
He also frequently telephones young prisoners in Buenos Aires, with whom the Vatican says he has a long-standing relationship with the purpose of giving them hope and rehabilitation.
Curran-Fromhold, named after a warden and deputy warden murdered in 1973, offers a window on the problems plaguing the prison system, illustrated by a recent video showing a guard violently hitting a detainee.
It currently holds 2,863 inmates and more than three-quarters of those in custody are awaiting trial.
These inmates often remain at the facility because they lack the means to pay their bail, even if the fee is just a few hundred dollars.