President Barack Obama will attend a Summit of the Americas in Panama this week, a gathering that could see the first substantive meeting between US and Cuban leaders in half a century.
The US president, fresh from reaching a tentative nuclear accord with arch-foe Iran, will jet to Jamaica then on to Panama City Thursday for a regular meeting of continental leaders.
Raul Castro -- who took control of the 11-million-strong still nominally Communist island from his brother Fidel seven years ago -- has confirmed he will be the first Cuban leader to attend.
But with days to go, diplomats are still discussing what form a Castro-Obama meeting might take.
Options range from a simple grip-and-grin photo, to an historic head-to-head sit down.
The leaders are together a lot of the time, at the summit said senior State Department official Roberta Jacobson. And so there will be an interaction with Raul Castro.
In December 2013, amid an upwelling of amity that followed Nelson Mandela's death, the pair shook hands briefly at a memorial service in Johannesburg.
This time round officials are looking for something a bit more substantive.
It's useful, obviously, to be able to have that contact and move things along so that we can get things done and open embassies and move ahead with this relationship, said Jacobson.
Last December, Obama declared he would put an end to an outdated approach to Cuba that was seeped in Cold War animosity and marked by crises that defined a generation -- the Bay of Pigs, the 1962 Missile Crisis.
Obama said diplomatic relations would be restored and the US would move toward ending a crippling embargo that Cuba alleges has cost it more than one trillion dollars over five decades.