WASHINGTON (AFP) - US President Barack Obama said on Friday that Cuba would change as a result of the communist-ruled island's rapprochement with Washington, but the improvements will not happen "overnight".
"I don't anticipate overnight changes," Mr Obama told reporters.
"It could happen fast. It could happen slower than I would like," he added. But "it's going to happen, and this change in policy is going to advance that."
But the US President, who coordinated with his Cuban counterpart, Mr Raul Castro, on the detente strategy that puts the former foes on track to normalise relations for the first time in more than half a century, dismissed the possibility of any immediate exchange of presidential visits.
"We're not at a stage here where me visiting Cuba or President Castro coming to the United States is in the cards," Mr Obama said in his final press conference of the year.
"There's nothing specific where we're trying to target some sort of visit on my part."
The White House, amid the flurry over Wednesday's announcement of the historic change in approach to Cuba, had signalled that a presidential visit to Havana was not out of the question.
As part of the policy shift, Mr Obama has ordered his administration to initiate steps to re-open its embassy and normalise ties, and study the prospects of lifting Cuba from the list of states that sponsor terrorism.
He also wants to eventually gain cooperation from Congress in lifting the 54-year-old US trade embargo on Cuba - sanctions that Mr Obama described as "self-defeating" - but acknowledged a congressional repeal would not be easy.
"We cannot unilaterally bring down the embargo," Mr Obama said.
"There's going to be a process where Congress digests it. There are bipartisan supporters of our new approach, there are bipartisan detractors of this new approach," he added.
"I think there will be a healthy debate inside of Congress. I will weigh in."
Several lawmakers, led by Senator Marco Rubio, who is Cuban-American, dismissed Mr Obama's change in Cuba policy as appeasing a dictator, and warned that the President was turning a blind eye to continued human rights abuses by the Cuban government.
Mr Obama insisted he did "share the concerns of dissidents there, and human rights activists, that this is still a regime that represses it people."
As for the changes likely to impact Cuba, "I think it will happen in fits and starts," Mr Obama said.
"But through engagement, we have a better chance of bringing about change than we would have otherwise."