Presidents Barack Obama and Raul Castro are expected to hold talks Saturday, a US official said, raising the prospect of the first substantive meeting between an American and Cuban leader in more than five decades. Obama and Castro are in Panama for the two-day Summit of the Americas, Cuba’s first, raising expectations of a landmark follow-up to their historic announcement on December 17 that their countries would restore ties severed since 1961. The meeting will be the first since Obama and Castro briefly shook hands at Nelson Mandela’s funeral in December 2013. An actual discussion would be the first substantive talks between US and Cuban leaders since 1956, when President Dwight Eisenhower met dictator Fulgencio Batista, who was toppled by Fidel Castro three years later.