US President Barack Obama and Cuban leader Raul Castro shook hands on Friday at a summit in Panama, a public gesture of mutual respect as the pair seek to restore diplomatic ties.
"At the Summit of the Americas this evening, President Obama and President Castro greeted each other and shook hands," said Bernadette Meehan, spokesperson for the National Security Council.
A White House official said, however, the pair did not have a "substantive conversation."
Castro's attendance marks the first time that Cuba has taken part in the Summit of the Americas in its 21-year history.
It also marked the first time that a US and Cuban leader had attended an official gathering together since relations between the two nations broke down in 1961.
Heads of state and government from the region, including Obama and Castro, will address the two-day event.
Before the talks opened, Castro could be seen laughing and chatting with Panamanian President Juan Carlos Varela and his wife on his arrival.
Obama also appeared to be in good spirits when he entered shortly after the Cuban leader, smiling and waving before turning to talk to Varela.
DW Washington correspondent Richard Walker retweeted the moment the two leaders shook hands at the start of the event:
A formal state dinner is scheduled to follow the opening ceremony.
A historic direct meeting between the two is planned on Saturday, the second and final day of the summit.
In December, Obama and Castro agreed to open the door to diplomacy and begin the process of improving relations.
However, Cuba had insisted that it be removed from the US list of state sponsors of terrorism before things could move forward, something which the US State Department said this week was "under review."
Earlier Friday, Obama met with Cuban dissidents as part of a civil society forum.
"As the United States begins a new chapter in our relationship with Cuba, we hope it will create an environment that improves the lives of the Cuban people," he said.
"Not because it's imposed by us, the United States, but through the talent and ingenuity and aspirations, and the conversation among Cubans from all walks of life," he added.
The summit, held every three years, has a central theme this year of "Prosperity with Equity: The Challenge of Cooperation in the Americas."
lw/cmk (AFP, dpa)