By Philip Pullella
VATICAN CITY (Reuters) - Pope Francis will meet prisoners, homeless people and immigrants as well as some of the world's most powerful leaders during his September trip to Cuba and the United States, according to a Vatican program issued on Tuesday.
Francis, the first Latin American pope, will become the first pontiff to address a joint session of the U.S. Congress during the much anticipated Sept. 19-27 trip.
That address and one scheduled to be delivered later to the United Nations will give him another chance to influence a major summit on climate change in Paris in December and discuss his recent encyclical "Laudato Si", which called for immediate action to save the planet from degradation.
He is the third pontiff to visit Cuba and presided over the Vatican mediation that led to the resumption of diplomatic ties between Washington and Havana last year after a rupture that lasted more than half a century.
He arrives in Havana on of Sept. 19 and is due to be greeted by President Raul Castro, younger brother of Fidel, who, Vatican sources say, he will meet depending on the revolutionary leader's health.
He holds private talks with Raul Castro on Sept. 20.
Like his predecessors John Paul and Benedict, he will celebrate mass in Havana's Revolution Square, with its huge mural of leftist guerrilla leader Che Guevara.
In Santiago he will meet families and pray in the basilica of the Virgin of Charity of Cobre, the patron of Cuba.
Francis arrives in Washington on Sept. 22 and hold talks with President Barack Obama the next day at the White House.
In the United States he is scheduled to canonize 18th-century Spanish Franciscan priest Junipero Serra, who founded missions in California. The Vatican has defended Serra against accusations that he brutalized Native Americans.
On the same day he addresses Congress, Francis will meet poor and homeless people at St. Patrick's parish in the U.S. capital.
Apart from his U.N. address, his two days in New York will include vespers with priests and nuns in St. Patrick's Cathedral, an inter-religious service at the Ground Zero site of the Sept. 11, 2001 attack on the World Trade Center, a meeting with immigrants and their children at a school in Manhattan's Harlem neighborhood and a Mass in Madison Square Garden.
Francis will spend the last two days of the trip in Philadelphia to close the World Meeting of Families, an international Catholic gathering that takes place in a different city around the world every three years.
In Philadelphia, he will also visit the Curran-Fromhold prison and preside at a rally on the theme of freedom of religion with Hispanics and other immigrants in Independence Mall.
Francis leaves on Sunday for a trip to Ecuador, Bolivia and Paraguay.