Cuba's deputy foreign minister has said the island's armed forces are actively preparing for a potential US military attack, in the starkest public acknowledgment yet of Havana's fears as the Trump administration intensifies its campaign against the communist-run government.

"Our military is always prepared, and in fact, it is preparing these days for the possibility of military aggression," Carlos Fernández de Cossío said in an interview with NBC’s Meet The Press on March 22, adding that regime change was "absolutely off the table." "We would be naive if not looking at what's happening around the world."

Fernández de Cossío said he hoped an invasion would not materialise and questioned what justification Washington could offer for military action against a neighbouring country, but the tone of his remarks reflected the degree to which relations between the two governments have deteriorated in recent months.

The warning comes as a Russian tanker carrying diesel fuel bound for Cuba was forced to divert after Washington intervened to block the shipment, underscoring the reach of the Trump administration's oil embargo against the island. The Sea Horse, carrying approximately 200,000 barrels of Russian diesel, altered its destination to Trinidad and Tobago on March 20 after the US clarified that Cuba does not have the right to receive Russian fuel, according to Bloomberg and maritime intelligence firm Kpler. Russian officials declined to comment when asked whether the cargo had been destined for Cuba.

The US Treasury has meanwhile added Cuba to the list of countries barred from receiving Russian oil, prohibiting transactions related to the sale, supply or delivery of crude and petroleum products of Russian origin to the island.

A second vessel, the Russian tanker Anatoly Kolodkin, is still crossing the Atlantic bound for the Cuban port of Matanzas, according to vessel-tracking data. Whether it will be permitted to discharge its cargo will serve as a further test of Washington's enforcement posture.

The interdiction of the Sea Horse lays bare the depth of Cuba's predicament. The island has received just two small oil deliveries in 2026, and last week suffered a 29-hour nationwide blackout after its fragile power grid, which relies on ageing oil-fired generators for 80% of its electricity, collapsed entirely, leaving its 10mn inhabitants without power. Another widespread outage was reported on March 21. The United Nations has warned the situation risks tipping into humanitarian catastrophe. Even before the grid failure, most Cubans had been enduring daily blackouts of 16 hours or more.

The crisis has its roots in the removal of subsidised Venezuelan oil following the capture of Cuban ally Nicolás Maduro in January, compounded by a US executive order threatening tariffs on any country supplying fuel to the island, a measure that has successfully deterred Mexico and other potential suppliers from maintaining shipments.

US Secretary of State Marco Rubio sharpened the White House's rhetoric last week, telling reporters that Cuba's leadership was incapable of restoring power to the island. "Cuba has an economy that doesn't work, and a political and governmental system that can't fix it, so they have to change dramatically," he said. Rubio, the first US-born Cuban to serve as secretary of state, has made no secret of his desire to see regime change in Havana.

President Donald Trump has gone further still, saying Cuba faces two options: a "friendly takeover" or what he described as a non-friendly alternative, adding that ultimately it did not matter which. He added that Washington could soon either reach an agreement with Havana or take other decisions regarding the island.

Despite the escalating rhetoric, both sides have acknowledged that direct talks are under way. Cuban President Miguel Díaz-Canel confirmed that officials from Washington and Havana have engaged in direct discussions in an effort to address their differences, though neither government has provided details of the negotiations.

The US and Cuba have remained bitter adversaries for 65 years, but the current confrontation marks one of the most acute episodes of tension since the Cold War. With Washington simultaneously managing Ukraine peace talks and a military campaign against Iran that has sent oil prices surging to their highest in years, the stakes of a further miscalculation in the Caribbean are growing by the day. Ostentatious defiance in public, backchannel pragmatism in private is a balancing act Cuba has played before, though one that grows harder to sustain with each passing blackout.