By Simon Lewis and Dave Sherwood WASHINGTON/HAVANA, Jan 15 - The U.S. State Department's top aid official on Thursday said Cuba's authorities must not interfere with a shipment of humanitarian aid to its people and suggested President Donald Trump could take action if Cuba does not comply.

Though Mr Trump’s intentions are murky, it is obvious that Cuba’s regime is now unusually vulnerable. It has survived for decades by courting powerful backers like the Soviet Union to prop up its state-controlled economy.

Mexico, which was providing some oil to Cuba before Maduro's capture by the U.S., has become an especially key fuel supplier to the island since the Venezuelan leader's arrest, which was accompanied by the U.S. interception of vessels carrying oil to Cuba. Sheinbaum has referred to oil as "humanitarian aid."

President Donald Trump warned Cuba there will be no more oil coming its way and told it to strike a deal, inciting a response from its leaders.

President Donald Trump has urged Cuba to make a deal with the U.S. as he uses Venezuela to crank up the pressure on the island.

Cuban President Miguel Díaz-Canel wrote that for 'relations between the U.S. and Cuba to progress, they must be based on international law rather than hostility, threats, and economic coercion.'

President Donald Trump said in a post on Truth Social that Cuba would no longer receive oil or money from Venezuela.

The president warned Cuba that “zero oil or money” will flow from Venezuela, urging Havana to “make a deal before it’s too late.”

The recent events in Venezuela have exposed the strategic risks of Cuba’s foreign entanglements.

Venezuela is Cuba's biggest oil supplier, but no cargoes have departed from Venezuelan ports to the Caribbean country since the capture of Venezuelan President Nicolas Maduro.