US President Donald Trump says no more Venezuelan oil or money will enter Cuba unless the communist-run island strikes a deal with Washington, ramping up pressure on the long-time Washington nemesis and provoking defiant words from the island's leadership.

Venezuela is Cuba's biggest oil supplier, but no cargoes have departed from Venezuelan ports to the Caribbean country since the seizure of Venezuelan President Nicolás Maduro by United States forces this month.

The US is enforcing a strict oil blockade on Venezuela, an OPEC country, shipping data shows.

Meanwhile, Caracas and Washington are progressing on a $US2 billion ($3 billion) deal to supply up to 50 million barrels of Venezuelan oil to the US, with proceeds to be deposited in US Treasury-supervised accounts, a major test of the emerging relationship between Mr Trump and interim president Delcy Rodríguez.

Donald Trump is warning Cuba to "make a deal" before it is too late. (Truth Social/@realdonaldtrump)

"THERE WILL BE NO MORE OIL OR MONEY GOING TO CUBA — ZERO! I strongly suggest they make a deal, BEFORE IT IS TOO LATE," Mr Trump wrote on his Truth Social platform on Sunday, local time.

"Cuba lived, for many years, on large amounts of OIL and MONEY from Venezuela."

Cuban President Miguel Díaz-Canel rejected Mr Trump's threat on social media, suggesting the US had no moral authority to force a deal on Cuba.

"Cuba is a free, independent, and sovereign nation. Nobody dictates what we do," Mr Díaz-Canel said on X.

"Cuba does not attack; it has been attacked by the US for 66 years, and it does not threaten; it prepares, ready to defend the homeland to the last drop of blood."

The US president did not elaborate on his suggested deal.

But Mr Trump's push on Cuba represents the latest escalation in his move to bring regional powers in line with the US and underscores the seriousness of the administration's ambition to dominate the Western Hemisphere.

Cuba is highly reliant on Venezuelan oil. (Reuters: Norlys Perez)

Mr Trump's top officials, including Secretary of State Marco Rubio, have made no secret of their expectation that the recent US intervention in Venezuela could push Cuba over the edge.

American officials have hardened their rhetoric against Cuba in recent weeks, though the two countries have been at odds since former leader Fidel Castro's 1959 revolution.

Cuba defends import rights

Cuban Foreign Minister Bruno Rodríguez said in another post on X on Sunday that Cuba had the right to import fuel from any suppliers willing to export it.