US President Donald Trump said on Monday Cuba is in "deep trouble" on a humanitarian basis and that US Secretary of State Marco Rubio was dealing with the issue which may or may not be a "friendly takeover."

"He's dealing (with it) and it may be a friendly takeover, it may not be a friendly takeover. Wouldn't really matter because they're really down to... as they say, fumes. They have no energy, they have no money," Trump, speaking at a news conference in Doral, Florida told reporters.

The Cuban government has said it is not in any high-level talks with the United States but has not outright denied press reports that US officials may be in informal talks with Raul Guillermo Rodriguez Castro, the grandson of former Cuban President Raul Castro.

Meanwhile, the United Nations’ coordinator on the island said on Monday that the UN is in talks with Washington over easing a crippling oil blockade on Cuba to allow in fuel for humanitarian purposes.

Francisco Pichon said UN officials had had "exchanges" with the Trump administration "in order to guarantee access to fuel" for emergency relief work.

The discussions also covered the fuel needs of Cuban NGOs that work with the United Nations and state-run health centres providing aid for the elderly, pregnant women and other vulnerable groups.

Trump has vowed to make US arch-foe Cuba his next target after Iran and the January overthrow of Venezuelan leader Nicolas Maduro.

In an attempt to precipitate the collapse of Cuba's communist leadership, he imposed an energy blockade on the nation in January.

The Cuban state has received no oil shipments for two months, forcing airlines to curtail or suspend flights to the island.

The blockade has also starved Cuba's power plants and farms of fuel and brought daily life to a near standstill.

Pichon said UN agencies in Cuba had been subject to strict fuel rationing, which had "compromised" their ability to fulfil their mandate.

UN staff were largely unable to carry out field work and UN agencies are having difficulty retrieving aid shipments from ports and airports, he added.

Havana accuses Trump of seeking to strangle Cuba's economy.

President Miguel Diaz-Canel has imposed emergency measures to conserve fuel, including strict fuel rationing.

Washington has claimed that Cuba represents an "extraordinary threat" to the United States to justify the blockade. (Agencies)



Edited by Cecil Wong