US secretary of state John Kerry departed Cuba Friday after a historic daylong visit to raise the US flag at the American embassy -- a milestone in Washington's rapprochement with its onetime foe.
The top US diplomat -- the first US secretary of state to visit the island in seven decades -- left aboard his official plane at 8 pm (0000 GMT).
Kerry called Friday for "genuine democracy" in Cuba as the American flag was raised over a US embassy in Havana for the first time in 54 years.
At a pageant-filled ceremony earlier Friday, he gave the cue to hoist the Stars and Stripes over the glass-and-concrete building on the Havana waterfront.
Three retired Marines who lowered the flag on January 4, 1961 -- when Washington severed ties with Havana at the height of the Cold War -- were present to hand the new flag to the Marine guard now charged with security at the embassy.
The symbolic moment served as a picture-perfect coda to eight months of rapid change since the December 17 rapprochement announcement by US President Barack Obama and Cuban counterpart Raul Castro, which paved the way for the two countries to reopen their embassies on July 20.
The first secretary of state to visit Cuba since 1945, Kerry said the shift in US policy did not mean Washington would stop pressing for change on the communist island.
"The leaders in Havana and the Cuban people should also know that the United States will always remain a champion of democratic principles and reforms," he said, in a speech delivered partly in Spanish.
"We remain convinced the people of Cuba would be best served by a genuine democracy where people are free to choose their leaders."
Kerry later shed his jacket and tie to take a stroll around Old Havana, stopping to buy a humidor and visit a cigar and rum shop as he got a tour of the colonial district surrounded by bodyguards, journalists and crowds of bemused onlookers.
Back in the United States, Obama's conservative opponents condemned the rapprochement with Washington's long-time enemy.
Republican presidential contender Marco Rubio, a Cuban-American senator from Florida, was among those who slammed the Obama administration for not inviting Cuban dissidents to the flag-raising ceremony.
"All the people in Cuba fighting for democracy -- when they protest, they are rounded up, arrested and beaten. None of them were invited to this event," he told Fox News.
Officials said Kerry later met privately with Cuban dissidents, who have long counted Washington as their main ally and have voiced concern the new thaw will leave them out in the cold.
Prominent dissident blogger Yoani Sanchez was among those present.
But Berta Soler, the leader of the Ladies in White -- one of the most high-profile dissident groups -- snubbed the event as a "waste (of) time."
Since the rapprochement was announced, the two sides have made progress on a number of divisive issues, most notably the removal of Cuba from Washington's list of "state sponsors of terrorism."
Cuban Foreign Minister Bruno Rodriguez said the country was ready to discuss any issue with the United States, including human rights.
But he warned that Cuba still has tough demands of its own, as the two sides pledged to continue talks through a high-level steering committee.
They include the full lifting of the "blockade" -- or economic embargo -- that the US has maintained on Cuba since 1962 and the return of the "usurped" Cuban territory of the American navy base at Guantanamo Bay, Rodriguez told a press conference.
Kerry was not scheduled to meet with either Castro or his elder brother Fidel, the icon who led Cuba from its 1959 revolution until his retirement in 2006.
Underlining the sticking points still complicating relations, Fidel Castro said in an essay published in Cuban state media Thursday -- his 89th birthday -- that the United States owes Cuba "many millions of dollars" because of the trade embargo.
Cuba says the embargo has cost it $116 billion.
The United States, for its part, says Cuba owes $7 billion to American citizens and companies whose property was seized after Castro came to power.
Kerry reiterated that the Obama administration "strongly favors" lifting the embargo.
But Obama faces an uphill battle as he needs approval from Congress, where both houses are currently controlled by his Republican opponents.
Kerry said lifting the embargo was a "two-way street" that would also require the Cuban government to allow greater freedoms.
"There's got to be some progress in the context of human rights because you can't normalize without that," he told journalists.
"There is no way Congress is going to vote to lift the embargo if they (the Cubans) are not moving with respect to issues of conscience."