US President Barack Obama and Cuban President Raul Castro are to meet in Panama in the first such encounter for more than 50 years.
The meeting will not be part of the official schedule at the Summit of the Americas, but the first face-to-face meeting between Cuban and American leaders since 1959 will provide one of the defining legacies of the Obama presidency.
Mr Obama and the Cuban president shook hands and exchanged words briefly at the opening ceremony on Friday night, a gesture that won both leaders praise from other leaders attending the summit.
Relations between the US and Cuba have been improving since the announcement in December that the two nations would restore diplomatic relations.
On the eve of the summit, US Secretary of State John Kerry met with his Cuban counterpart Bruno Rodriguez for a “lengthy and very constructive discussion”, according to a US state department official.
Barack Obama is expected to remove Cuba from the US list of state sponsors of terrorism in the next week. The move should help lead to a full restoration of diplomatic ties and the opening of embassies in Havana and Washington.
Cuba was placed on the list in 1982, accused of offering sanctuary to militants involved in terrorist acts. The country has faced tough sanctions as well as bans on exports and arms sales because of its spot on the list. The three other countries still on the list are Iran, Sudan and Syria.
Our Cuba policy, instead of isolating Cuba, was isolating the United States in our own backyard. Ben Rhodes
Washington imposed trade sanctions on Cuba from 1960 and broke off diplomatic relations with Cuba in 1961. The two countries then became Cold War enemies for decades.
In the last four months the US president has agreed to an end to hostility and using executive powers to ease some trade and travel restrictions.
Mr Obama’s deputy national security adviser, Ben Rhodes, said on Friday: “Our Cuba policy, instead of isolating Cuba, was isolating the United States in our own backyard.”
President Obama spoke over the phone with President Castro on Wednesday in what was only the second known conversation between the leaders of the US and Cuba in over half a century.
The two presidents made history in December 2013 when Obama and Castro shook hands at Nelson Mandela’s funeral in Johannesburg, South Africa.
The US still faces the prospect of animosity at the summit in the form of President Nicolas Maduro of Venezuela, who has vowed to use the meeting to rail against the United States. Barack Obama angered Maduro by imposing sanctions against seven Venezuelan officials accused of human rights abuses.
This is the third time Obama will attend the Summit of the Americas, which is held every three years. Both his previous visits were overshadowed by US insistence that Cube be excluded.
Back on US soil, Republicans have been scathing about the administration’s new Cuba policy.
When the White House announced a thawing of relations between the two countries in December, US Senator Marco Rubio led the criticism of Obama.
“I don’t care if the polls say that 99 percent of people believe we should normalize relations in Cuba,” he said at the time. “I don’t care if 99 percent of people in polls disagree with my position. This is my position, and I feel passionately about it.”