Us - cuba relations global praise for normalistion of ties.
Cubans celebrated the release of three high-profile prisoners who were serving
World leaders have welcomed a historic move by the US to end more than 50 years of hostility towards Cuba and restore diplomatic relations.
Pope Francis joined leaders from Latin America and Europe in praising the "historic" deal which saw the release of prisoners from both countries.
But dozens of dissident Cubans oppose the move, which some Republicans have labelled a "retreat" by the US.
US-Cuban ties have been frozen since the early 1960s.
President Obama said the "rigid and outdated policy" of isolating Cuba since then had clearly failed and that it was time for a new approach.
Mr Castro, meanwhile, has urged the US to ends its trade embargo, which has been in place since the Cuba turned to communism more than 50 years ago.
The Cuban government blames the US embargo for economic hardship on the island
But power to lift the embargo, which Mr Castro says has caused "enormous human and economic damage", lies with the US Congress, and correspondents say many Republicans are still deeply opposed to this.
'Beginning of the end' Leading the praise, Pope Francis sent "warm congratulations" to Mr Obama and Cuban President Raul Castro for overcoming "the difficulties which have marked their recent history".
The announcement followed more than a year of secret talks in Canada and at the Vatican, directly involving the pontiff.
The European Union, which is in the process of normalising ties with Cuba, described the move as a "historical turning point", while leaders meeting at a Latin America summit in Argentina broke into applause at the news.
US national Alan Gross celebrates after his release from five years of imprisonment in Cuba
The rapprochement was not received well by some exiled Cubans living in the US state of Florida
Cuban TV aired footage of President Castro (L) greeting one of the intelligence agents released from the US
Chilean Foreign Minister Heraldo Munoz hailed it as "the beginning of the end of the Cold War in the Americas".
Venezuelan President Nicolas Maduro, whose predecessor Hugo Chavez was a close ally of Fidel Castro, said it was a "moral victory" and "victory for Fidel".
Former US Secretary of State Hillary Clinton said increased US engagement in Cuba in the future should "encourage real and lasting reforms for the Cuban people".
"And the other nations of the Americas should join us in this effort," she added.