(CNN) President-elect Donald Trump threatened Monday to "terminate" the Obama administration's efforts to normalize US-Cuba relations.

"If Cuba is unwilling to make a better deal for the Cuban people, the Cuban/American people and the U.S. as a whole, I will terminate the deal," Trump tweeted.

Trump's threat came after the death of long-time Cuban dictator Fidel Castro, whose passing on Saturday he marked with another tweet. "Fidel Castro is dead!" the president-elect wrote, before issuing a statement condemning the Cuban leader.

Trump appears to be aiming to use the coming political transition in Cuba -- likely to be smoothed by the presence of Castro's brother Raul -- as a possible opportunity to renegotiate the terms of the rapprochement between the US and Cuba.

Speaking later Monday at the White House, spokesman Josh Earnest said the death of Castro is unlikely to have any impact on US effort to normalize relations between the two countries.

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