ANDREWS AIR FORCE BASE, Maryland (AFP) - Pope Francis arrived in the United States on Tuesday for his first visit - a historic six-day trip to the spiritual home of capitalism after his tour of communist-ruled Cuba.

The 78-year-old Argentine pontiff stepped onto US soil for the first time at Andrews Air Force Base outside Washington.

A crowd of well-wishers erupted in cheers and chanted as Francis emerged from his plane in his traditional papal whites.

US President Barack Obama, his wife Michelle and their daughters Malia and Sasha shook hands with Francis on the red carpet rolled out on the tarmac. The pope then made his way down the reception line of dignitaries and senior church figures.

US Catholic leaders and a select crowd of several hundred well-wishers were also on hand to greet the pope, who waved to the cheering crowd.

A small group of children from Catholic schools in the Washington area were brought forward to welcome the pontiff.

Mr Obama will host the Jesuit pope at the White House on Wednesday. Pope Francis will make two key speeches during his visit, addressing the US Congress on Thursday and the United Nations on Friday.

On the plane from Cuba to the United States, the pope told reporters that he would not specifically raise Washington's embargo on Havana in his speech before American lawmakers, but expressed his opposition to it.

"The Holy See is against this embargo, but it is against all embargoes," he said.

Topics will include critiques of the dominance of finance and technology; a condemnation of world powers over the conflicts gripping the planet; appeals to protect and welcome immigrants; and climate change, according to Vatican sources.

The visit will take place under tight security, with US authorities on top alert to handle the complexities of protecting a pope who insists on travelling in an open vehicle to be closer to the masses.

Authorities are facing a particular security headache in New York, where Francis plans to criss-cross Manhattan at a time when 170 world leaders will be in town for the UN General Assembly.

He will preside over an inter-faith ceremony at Ground Zero, visit a Harlem Catholic school and greet crowds on a procession through Central Park.

He will wrap up his trip Saturday and Sunday in Philadelphia at an international festival of Catholic families.

The pope arrived from Cuba, where he visited three cities in four days, said three masses before adoring crowds and met President Raul Castro and his big brother Fidel, the men who have ruled the communist island since its 1959 revolution.

The pontiff, the first from Latin America, played a key role in brokering the recent rapprochement between Washington and Havana, which resulted in the restoration of diplomatic ties in July after more than half a century.

In the United States, he will find an American public that widely respects him, but has a less favourable view of the Catholic Church.

While 81 per cent of Catholics have a positive view of the Church, only fifty-five percent of Americans as a whole do, according to a new poll conducted by The Washington Post and ABC News earlier this month.

But for some critics, the dominant themes of his papacy - his critique of consumerism, calls to embrace poverty and condemnation of a "throwaway culture" - sound suspiciously like an indictment of the American way of life.

That was underlined ahead of his trip when Republican Congressman Paul Gosar, who is Catholic, declared he would boycott the pontiff's historic address to Congress to protest his "leftist" views.

The pope has been active in urging compassion, including for those historically shunned by the Church, and for calling for action against economic inequality and environmental degradation.

Americans in general approve of those efforts, with 54 per cent wanting him to "continue as he has been" and another 23 per cent urging him to be even more active.

During his Cuba visit, Francis discreetly refrained from chastising the communist regime for its crackdowns on dissidents and curbs on civil liberties.

Before leaving the island on Tuesday, Francis said mass in Cuba's second city Santiago, cradle of the Castros' uprising against dictator Fulgencio Batista, calling for a new kind of "revolution." Speaking at a basilica to Our Lady of Charity of El Cobre, Cuba's patron saint - a mixed-race Mary that symbolizes the island's intertwined Spanish and African roots - he praised her as the embodiment of a "revolution of tenderness."

He urged Cubans to follow her example "to build bridges, to break down walls, to sow seeds of reconciliation", in comments that appeared to allude to the nascent reconciliation across the Florida Straits.

Francis then addressed an audience of families, asking for their prayers as he prepares for a synod on the family next month that has unleashed internal conflicts among the Roman Catholic clergy over sensitive issues such as divorce, homosexuality and unmarried couples.