Fears are growing that Donald Trump may be preparing for military action in Cuba as Washington continues to ramp up rhetoric against the island’s communist government.Donald Trump dramatically turned up the heat on Thursday as he told reporters he could be the president who finally takes direct action against Havana after decades of failed threats from Washington.“Other presidents have looked at this for 50, 60 years,” Trump said. “It looks like I’ll be the one that does it.”Separately, his secretary of state, Marco Rubio, said the chances of a negotiated settlement with Havana were “not high” and cast the dispute as a threat to American national security.In response, Cuba’s foreign minister Bruno Rodriguez accused Rubio of lying “to instigate a military aggression that would provoke the shedding of Cuban and American blood”.Secretary of State Marco Rubio — a longtime Cuba hawk and the son of Cuban immigrants — warned that the White House is done playing games with the regime (AFP/Getty)The escalation came just a day after the US charged Cuba’s former president Raúl Castro with murder over the downing of two planes in 1996, which resulted in the killing of US nationals.Cuba’s current president, Miguel Díaz-Canel, blasted the charges as a “political stunt” designed to justify possible American aggression against the island.Trump has openly discussed toppling Cuba’s regime and demands vague political reforms. The dispute has invited pointed criticism from Russia and China, urging Washington to stop threatening Cuba with force.Meanwhile, Cubans continue to suffer from a fuel crisis exacerbated by a US oil blockade, with citizens still experiencing food shortages and recurring blackouts.For months, the US president has been clear in his intentions with the Caribbean island. “I do believe I’ll have the honour of taking Cuba,” he told reporters in March. “That would be good… I think I can do anything I want with it.”A woman carries her baby while looking at her mobile phone in Havana on May 20, as the island continues to face food shortages and blackouts (AFP/Getty)Maintaining strategic ambiguity, Trump then said in a string of mixed messages on Wednesday that while “we have to help Cuban people”, he can’t say what’s next for the island nation, and there “won’t be escalation in Cuba”.Havana has responded forcefully to the threats from Washington, accusing it of “economic warfare” and saying suggestions that Washington could “liberate” Cuba were cynical and hypocritical. Fresh sanctions on the Cuban regime were announced on 1 May by the White House, who said they would target entities and individuals that are complicit with alleged corruption and rights violations by the Cuban government and its security apparatus. What have US and Cuban officials said?The US and Cuba have had strained relations for decades, stemming from the island’s communist revolution and the disastrous Washington-backed Bay of Pigs invasion in 1961. President Trump has pushed for regime change in Cuba, where communists ‌have been in charge since Fidel Castro led a revolution in 1959.But Rubio insists the United States would prefer a diplomatic solution to the crisis.“That remains our preference with Cuba,” he told reporters this week. Cuba’s Raul Castro (R) speaks with his Venezuelan counterpart Hugo Chavez (L) in 2010 (Reuters)“I'm just being honest with you, you know, the likelihood of that happening, given who we're dealing with right now, is not high. But if they have a change of heart, you know, we're here. And in the meantime, we'll keep doing what we need to do.”Cuban Foreign Minister Bruno Rodriguez accused Rubio of inciting military aggression and falsely labeling Cuba a state sponsor of terrorism.For months, the United States has upped rhetoric against the regime, buoyed by the successful ousting of Venezuelan president Nicolas Maduro in January.Speaking in early March after launching the US-Israeli war on Iran, Trump told Fox News: “Cuba’s next. They’re going to follow this communist dictatorship in Cuba. Their days are numbered.”Cuba's Foreign Minister Bruno Rodriguez speaks during a press conference in Havana, Cuba (Reuters)The White House has said the Cuban regime “aligns itself with countries and malign actors hostile to the United States, going so far as to facilitate their military and intelligence operations”. It accused the country of hosting “foreign adversary facilities focused on targeting and exploiting sensitive national security information from the United States”. What has been the impact of US action so far?The United States announced murder charges against former Cuban President Raul Castro on Wednesday, in a sharp escalation of tensions between the longtime Cold War rivals.The indictment prompted speculation that US forces could launch an operation to capture him. But so far, the US has stopped short of direct military intervention.Rubio did say on Thursday that the US had arrested the sister of one of the top officials of a military-run conglomerate in Cuba responsible for some of the most lucrative parts of the country’s economy.Adys Lastres Morera was alleged to be “aiding Havana’s communist regime” while living in Florida, Rubio said.Cubans gather outside Versailles Cafe after the U.S. Department of Justice announced criminal charges against Raul Castro, in Miami, Florida, on 20 May (Reuters)It is not clear exactly what a US military operation in Cuba would look like – and no plans have been briefed to the media despite Trump’s threats. It could be a “friendly takeover”, a “not so friendly takeover” or a “forced restructuring of the Cuban state”, foreign policy expert Dr Izabela Pereira Watts wrote in an analysis for the Lowy Institute think-tank. But Washington has already “severed the island’s jugular” by choking Havana’s access to imported fuel, after taking over Venezuela’s oil assets during its operation against the Maduro regime, she said. The move has had a damaging impact on Cuba’s internal logistics, Dr Watts says. Flights have been cancelled, schools suspended and hospitals are struggling to provide basic emergency care.What could a US attack look like?What the precise aims of US action on Cuba would be is unclear, but experts have suggested that Trump will seek regime change. Deposing the country’s leadership would be a repeat of the US operation in Venezuela in January, when special forces arrested former president Nicolas Maduro in a stunning raid. But the Caracas government remains in place with Maduro’s allies still at the helm, with his former vice president Delcy Rodriguez currently installed as leader. People walk trough a street, with an oil tanker ship in the background, in Matanzas, Cuba on March 30 (AFP/Getty)In Iran, despite suggestions from the Trump administration that regime change could be possible, America’s goals have been more focused on destroying the country’s nuclear programme and military infrastructure. Dr Watts believes the US is more likely to pursue economic action ahead of a military operation in Cuba. “By pushing the Cuban economy to the brink of a humanitarian abyss, Washington believes it can force the Communist Party of Cuba to accept a market-oriented transition in exchange for political survival,” she says.But Cuba’s government will not take a risk, especially given Trump’s record in recent months, with Diaz-Canel warning Havana is “preparing in case we have to move to a state of war”.