HAVANA (AFP) - Pope Francis on Saturday urged the United States and Cuba to pursue their nascent reconciliation as he arrived in Havana on the first leg of a high-profile trip that will also take him to America.

Cuban President Raul Castro was at Jose Marti airport to greet the Argentine pontiff, whose white skullcap blew off in a tropical wind as he exited his Alitalia plane.

But Francis barely skipped a beat, blessing a group of children who greeted him with flowers and then - highlighting his role in brokering the Cold War foes' historic rapprochement - calling on Castro and US President Barack Obama not to falter on the road to closer ties.

"For some months now, we have witnessed an event which fills us with hope: the process of normalising relations between two peoples following years of estrangement," he said in a speech delivered on the tarmac.

"I urge political leaders to persevere on this path and to develop all its potentialities... as an example of reconciliation for the entire world."

He also pledged the Church's support for the Cuban people, who face tight restrictions on their civil liberties under the communist regime and bear the weight of the economic woes that decades of isolation have wrought on the island.

Recalling Pope Benedict XVI's 2012 trip to Cuba and John Paul II's visit in 1998, Francis said that "today we renew those bonds of cooperation and friendship, so that the Church can continue to support and encourage the Cuban people in their hopes and concerns," he said.

He added that the Church needed "the freedom and the means" to do its work on the island, which was an atheist state for more than three decades until a gradual reconciliation with religion in which John Paul II's visit played a key part.

Francis, 78, looked tired from the long trip from Rome, but smiled warmly at the throngs of well-wishers who greeted him.

His tour will also take him on his first-ever visit to the United States, where he will give landmark speeches to the US Congress and the UN General Assembly next week.

Thousands of people lined the road into Havana from the airport, which was decked out with giant posters of the Pope.

"We hope God will help us and that when his holiness goes to the United States, he can be our advocate," said 32-year-old Yudelkis Geigel.

"He's Latin American, he's Argentine, he feels for us and our need to end this blockade," she said - the word commonly used here for the US embargo on Cuba.

NEW OVERTURE FROM WASHINGTON

The visit comes on the heels of the historic announcement of the US-Cuban rapprochement, which paved the way for the estranged neighbors to renew diplomatic relations in July - a moment that Francis, the first Latin American pope, helped facilitate in secret negotiations.

As well as Havana, he is due to visit Holguin and Santiago, birthplace of Cuba's 1959 revolution.

He will likely meet Castro's predecessor and brother Fidel during his three-night stay on the Caribbean island.

Francis shares the Castro brothers' radical critique of global capitalism, but has not shied from prodding their one-party regime toward greater respect for civil rights and religious freedom.

That such a small state has been smothered with papal attention reflects the importance the Vatican attaches to the fate of Cuba's Catholics, who have won greater freedoms as part of a diplomatic process in which the Holy See has also championed the case for an easing of the US embargo.

In the run-up to Francis's arrival, the Cuban government announced the release of more than 3,500 prisoners, significantly more than were liberated before previous papal visits.

The United States for its part announced a further loosening of restrictions on business and travel with Cuba.

NEXT STOP: CAPITALISM CENTRAL

While he got a warm welcome in Cuba, the outcome of the US leg of Francis' 10th overseas trip looks more uncertain.

For some observers, the dominant themes of Francis's papacy - concern for the poor, his strong stance in favor of action on global warming and his critique of consumerism - can be read as an indictment of the American way of life.

But he is sure to be treated as a special guest by most Americans, from the prisoners he will meet in Philadelphia to Obama, who will greet him personally on his arrival Tuesday at Andrews Air Force Base outside Washington.

While in New York, the pontiff will preside over a multi-faith service at Ground Zero against terrorism and in memory of the victims of the September 2001 attacks on the United States.

Some 1.5 million people are expected for the final mass of the trip, in Philadelphia at an international festival of Catholic families.