US President Barack Obama arrives in Cuba

"Que bol Cuba?" Obama tweeted on landing yesterday, using Cuban slang to ask what's going on.

"Just touched down here, looking forward to meeting and hearing directly from the Cuban people." 

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

He was greeted on the tarmac by Cuban Foreign Minister Bruno Rodriguez, before loading into his bulky limousine, nicknamed "The beast." 

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

Seeking to leave a historic foreign policy mark in his final year in office, Obama will tour the newly reopened US embassy and old town Havana late yesterday, hold talks with Cuban President Raul Castro today and attend a baseball game before leaving tomorrow.

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

"A president of the United States in Cuba arriving in Havana on his Air Force One," wrote popular Cuban writer Leonardo Padura on the Cafefuerte blog.

"Never in my dreams or nightmares could we have imagined that we'd see such a thing." 

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 was due to stroll later and police, especially plainclothes, were out in large numbers.

But minutes before Obama took off for Cuba, police in Havana arrested dozens of people from a banned group demanding greater human rights, AFP reporters said.

Republicans and some human rights activists have criticised 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." 

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