Barack Obama on Sunday became the first US president in 88 years to visit Cuba, hailing an "historic opportunity" to cast aside decades of Cold War enmity with the communist state.

Touching down in Havana, Obama began the landmark trip with an overture to Cuba's citizens -- "Que bola Cuba?," he tweeted, using local slang to ask "what's up?"

A smiling Obama then emerged from Air Force One with his wife Michelle and their two daughters Sasha and Malia, clutching umbrellas to shield themselves from a warm afternoon rain shower.

Obama is not only the first sitting US leader to visit Cuba since Fidel Castro's guerrillas overthrew the US-backed government of Fulgencio Batista in 1959, but the first since President Calvin Coolidge in 1928.

PHOTOS: Obama begins historic visit to Cuba

"President Coolidge came on a battleship, it took him three days to get here. It only took me three hours," Obama joked during a meeting with staff from the freshly reopened US embassy.

"This is a historic visit and a historic opportunity," he said.

For Cubans dreaming of escaping isolation and reinvigorating their threadbare economy, the visit has created huge excitement.

But just hours before Obama's arrival there was an ominous reminder of their government's controlling hand.

Police in Havana arrested dozens of people from a banned group demanding greater human rights, AFP reporters witnessed.

The protesters were from the Ladies in White, formed by wives of former political prisoners. Police bundled them into vehicles outside a church where they attempt to hold protests almost every Sunday.

On the Malecon, the famous seaside esplanade where Havana residents love to gather on warm evenings, 42-year-old civil engineer Ariel Hernandez expressed hope for change.

"Since I was a child I've heard the story of the revolution and this was really the story of being against the United States," he said. "It's truly a historic moment, it's huge."

"For me, I really think the future will change."



Legacy

Obama is looking to leave a historic foreign policy mark in his final year in office.

After meeting embassy staff he toured old town Havana, greeting the Archbishop of Havana, Jaime Ortega, who helped facilitate secret talks with the government.

For days, Havana's old town has been crawling with painters sprucing up the picturesque neighbourhood and the Stars and Stripes -- long the enemy flag -- has appeared over numerous buildings.

Early Sunday, cleaners swept the narrow, cobbled streets where Obama later took a stroll and police, especially plainclothes agents from the Department of State Security, were out in large numbers.

He is scheduled to hold talks with Cuban President Raul Castro on Monday and attend a baseball game before leaving Tuesday.

Republicans and some human rights activists have criticized Obama for dealing with Castro, given the lack of political, media and economic freedom in a country where the Communist Party retains tight control.

Dissidents called for "radical change" on the eve of the visit, but the Castro government warned that lectures on democracy would be "absolutely off the table."

The White House's deputy national security adviser, Ben Rhodes, insists that the subject will be brought up. Obama will meet members of Cuba's beleaguered opposition and on Tuesday will give a speech at the National Theater carried live on Cuban television.


'Soft war'

The United States spent decades trying to topple Cuba's communist government.

Washington attempted economic strangulation, the failed 1961 Bay of Pigs invasion, and CIA assassination plots against Fidel Castro -- including the legendary, but unproven story of sending him an exploding cigar.

Now, after so many failures, Obama has bet that soft power will achieve what muscle could not. The aim, Rhodes said, is to make "the process of normalization irreversible."

Although a decades-long US economic embargo remains in place -- and can only be removed by the Republican-controlled Congress -- large cracks in the sanctions regime are appearing.

Obama hopes that a host of incremental and seemingly technical steps will open Cuba's economy, transforming the island economically and politically, backers of the policy say.

Lawmakers including House Minority Leader Nancy Pelosi were with Obama, while a delegation of political and business leaders was traveling separately.

"It's a soft war using visitors as the soldiers, commercial airlines as the air force, and cruise ships as the navy," said John Kavulich, president of the US-Cuba Trade and Economic Council.

Cuba's regime, which for decades defined itself as the people's bulwark against the Yankee enemy, has bowed to the fact that Cubans would rather do business than make war.

And as if Obama's arrival were not enough to illustrate the sea change in Cuba, the Rolling Stones -- a symbol of the cultural imperialism that communist leaders raged against -- are playing a free concert in Havana on Friday.