Pope Benedict has called on Cubans to build a "renewed and open society" at the start of a three-day visit to the Communist island.
The pope delivered an open-air Mass in Santiago hours after being welcomed in the eastern Cuban city by President Raul Castro.
Before Mass, one man shouting "Down with communism" was taken away by security officials.
Earlier, Benedict recalled the ground-breaking visit to Cuba fourteen years ago by his predecessor, Pope John Paul, saying it left "an indelible mark on the soul of all Cubans," whether believers or not.
"One of the important fruits of that visit was the inauguration of a new phase in the relationship in Cuba between Church and State, in a new spirit of cooperation and trust, even if many areas remain in which greater progress can and ought to be made, especially as regards the indispensable public contribution that religion is called to make in the life of society," the pontiff said.
Later today, Benedict travels on to Havana.
Benedict arrives in Cuba just days after calling the island's Marxist system outdated.
Fewer than 10 percent of Cubans are practicing Catholics.
Based on AP and Reuters reporting