Donald Trump has said he is restoring some travel and economic restrictions on Cuba that were lifted by Barack Obama's administration.
The US President challenged the communist government of Raul Castro to negotiate a better deal for Cubans and Cuban-Americans.
Announcing the changes during a speech in Miami, Mr Trump said Cuba had secured far too many concessions from the US in the "misguided".
He said penalties on Cuba would remain in place until its government releases political prisoners, stops abusing dissidents and respects freedom of expression.
"America has rejected the Cuban people's oppressors," Mr Trump said in a crowded, sweltering auditorium. "They are rejected officially today - rejected."
Though Mr Trump's announcement stops short of a full reversal of the Cuba rapprochement, it targets the travel and economic engagement between the countries that has blossomed in the short time since relations were restored.
The goal is to halt the flow of US cash to the country's military and security services in a bid to increase pressure on Cuba's government.
Embassies in Havana and Washington will remain open. US airlines and cruise ships will still be allowed to serve the island 90 miles south of Florida.
The "wet foot, dry foot" policy, which once let most Cuban migrants stay if they made it to US soil but was ended under Mr Obama, will remain terminated. Remittances to Cuba will not be cut off.
But individual "people-to-people" trips by Americans to Cuba, allowed by Mr Obama for the first time in decades, will again be prohibited.
Mr Trump described his move as an effort to ramp up pressure to create a "free Cuba" after more than half a century of communism.
"I do believe that end is in the very near future," he said.
In a statement on government-run websites and television, President Castro's administration said Mr Trump's speech was "loaded with hostile rhetoric that recalls the times of open confrontation".