Sanders said global wealth inequality, a subject championed by Pope Francis, has only become worse.

"Our very soul as a nation has suffered as the public lost faith in political and social institutions," he said in his speech, which he followed up with comments to reporters in Vatican City, hours after Thursday night's Democratic debate in New York.

ADVERTISEMENT Sanders argued that big money in politics and powerful financial interests led to more than financial bubbles and falling living standards but broader cynicism in the United States and around the world.

The Vermont senator made his remarks during a workshop at a conference on social, economic and environmental issues hosted by The Pontifical Academy of Social Sciences.

Sanders is not expected to meet with Francis himself during the visit, though he is reportedly staying at the hotel where Francis lives on Friday night.

The decision by the Democratic candidate to leave New York days before that state's primary was seen as a political risk.

Sanders faces an uphill battle for delegates to secure the Democratic nomination and is hoping to rally economic progressives and shore up support from Catholics with a trip to Vatican City.

There were days of speculation over whether Sanders would meet with the pope himself during his trip, though spokesmen for the pontiff had ruled out such a meeting ahead of his speech.

Bishop Marcelo Sánchez Sorondo, chancellor of the academy who had invited him to speak at the workshop, read a message from the pontiff shortly before Sanders delivered his remarks in which Francis apologized for not being able to attend the workshop later in the day, noting preparations for a trip to the Greek island of Lesbos on Saturday.