Washington: The United States and Cuba on Wednesday agreed a historic deal to re-establish full diplomatic relations, severed 54 years ago in the heat of the Cold War.
Presidents Barack Obama and Raul Castro exchanged letters agreeing to unfreeze ties on July 20, when embassies in Washington and Havana can be reopened.
Obama hailed the deal as a "historic step forward" that would end a failed and archaic US policy of isolating the still Communist-ruled island.
Obama - who was born the year the US embassy was closed in 1961 - called on domestic critics to stop "clinging to a policy that was not working."
He pressed the Republican-controlled Congress to end a throttling US trade embargo set up in 1962.
"It's long past time for us to realize that this approach doesn't work," he said in a White House Rose Garden address.
"It hasn't worked for 50 years. It shuts America out of Cuba's future and it only makes life worse for the Cuban people."
US president Dwight Eisenhower shuttered the US embassy in Havana after a guerrilla insurgency brought Fidel Castro to power and placed Cuba firmly within the orbit of the Soviet Union.
The embassy closure foreshadowed conflagrations across the Straits of Florida that would define an era: from the failed Bay of Pigs invasion to the crisis over Russian missile sites in Cuba.
Raul Castro on Wednesday expressed his desire to "develop respectful and cooperative relations between our two peoples and governments," in his letter to Obama.
Half a lifetime ago, Castro landed in Cuba with his older brother Fidel, Argentine revolutionary Che Guevara and dozens of other rebels to overthrow the unelected US-backed government.
On July 20, Raul Castro will send Foreign Minister Bruno Rodriguez to open the Cuban embassy in Washington.
No date was set for opening the US embassy in Cuba, but Obama announced that "later this summer, Secretary John Kerry will travel to Havana formally to proudly raise the American flag over our embassy once more."
Both countries are currently represented by an "interests section" within the embassies of Switzerland.
Polls show a majority of Americans support Obama's efforts to improve ties.
South American countries were also broadly supportive of the breakthrough.
The foreign ministries of Argentina and Ecuador spoke out in support of the deal and Brazil's president Dilma Rousseff hailed it while in Washington Tuesday.
But opponents could yet pose problems for further rapprochement.
Republican presidential candidates who have ties to Cuba, including Marco Rubio and Ted Cruz, have been outspoken in their opposition to the thaw.
Rubio, a senator from Florida, accused Obama of giving concessions as Cuba continued to stifle democracy.
"It is time for our unilateral concessions to this odious regime to end," he said.
"I intend to oppose the confirmation of an ambassador to Cuba until these issues are addressed."
Cruz, from Texas, said he would try to halt funds for embassy construction in Havana until the president demonstrates "progress" in helping the Cuban people.
Senator Bob Menendez, a Democrat, also weighed in against the deal.
"Once again the (Cuban) regime is being rewarded while they jail dissidents, silence political opponents, and harbor American fugitives and cop killers," he said in a statement.
Obama's plan of lifting the embargo will be an uphill battle, according to analyst Diego Moya-Ocampos of IHS Country Risk.
"Key sanctions are unlikely to be fully removed until the US Congress lifts the US embargo on Cuba, something unlikely to take place before 2018 when incumbent president Raul Castro is expected to step down," he said.
After 18 months of secret talks between Havana and Washington - and aided by the Vatican - the two countries agreed in December to begin warming relations.
Obama and Raul Castro held a historic meeting in Panama in April - the first sit-down between leaders of the United States and Cuba since 1956.
Travel and communications restrictions between the two countries have been significantly eased.
In May, the United States paved the way for further rapprochement by taking Cuba off the list of state sponsors of terrorism.
Final negotiations on re-opening the embassies had been dominated by discussions over the free movement of diplomats.
A senior State Department official said that diplomats would now need to simply inform the Cuban authorities about their movements, rather than ask permission.
Kerry - who will become the first secretary of state to visit Cuba since 1945 - said the embassy would help diplomats to "interact more frequently, and frankly more broadly and effectively, with the Cuban people."
It would, he said, also help engage the Cuban government, with whom there were still "sharp differences" over democracy and human rights.