Among the verdant gardens of Havana’s diplomatic quarter, Siboney, ambassadors from countries traditionally allied to the United States are expressing increasing frustration with Washington’s attempt to unseat Cuba’s government, while simultaneously drawing up plans to draw down their missions.

Cuba is in crisis. Already reeling from a four-year economic slump, worsened by hyper-inflation and the migration of nearly 20% of the population, the 67-year-old communist government is at its weakest. After Washington’s successful military operation against Cuba’s ally Venezuela at the beginning of January, the US administration is actively seeking regime change.

The Guardian spoke to more than five top-level officials from different countries, and heard complaints that the US charge d’affaires, Mike Hammer, has failed to share any sort of detailed plan beyond bringing the island to a standstill by starving it of oil. One said: “There’s talk of human rights, and that this is the year Cuba changes – but little talk of what happens afterwards.”

Some hope that rumoured high-level discussions in Mexico between the Cuban government – in the form of Gen Alejandro Castro Espín, son of Cuba’s 94-year-old former president Raúl Castro – and US officials might produce a deal, but as yet there are no signs of progress.

Instead, diplomats in Havana are preparing for an alternative tactic: the country being starved until people take to the streets and the US can step in. “We’re trying to keep a cool head,” said one ambassador. “Embassies are built on planning for the unexpected – hopefully before it becomes expected,” said another.

Stoking concerns is news that lack of fuel is hampering the UN World Food Programme’s efforts to relieve suffering from last year’s Hurricane Melissa. The organisation, which keeps a low-key presence on the island, is now having to draw up plans for a new, far larger crisis. “We’re already seeing the impact in the availability of fresh produce in the cities,” said Étienne Labande, the WFP’s country director.

Diplomats expressed concern at how fast the lack of fuel – for electricity, water and the transport of food – could cause extreme suffering. “It’s a matter of weeks,” said one. “The view is that people in rural villages like Viñales may be OK, but those in the cities would be at terrible risk.”

Cuba’s latest crisis follows an executive order signed by Donald Trump in January imposing tariffs on any country supplying Cuba with oil. Despite outrage from Cuba’s traditional allies China and Russia, the threat has proved effective.

Even Mexico, which last year supplanted Venezuela as the island’s largest supplier, has ceased sending tankers, although its president, Claudia Sheinbaum, warned of a humanitarian disaster on the island and sent 800 tons of aid. “No one can ignore the situation that the Cuban people are currently experiencing because of the sanctions that the United States is imposing in a very unfair manner,” she said on Tuesday.

At a party at the US residence on 28 January, Hammer referred to the 68-year US embargo on the island, telling guests: “The Cubans have complained for years about ‘the blockade’, but now there is going to be a real blockade.”

He began a tour of eastern Cuba shortly afterwards, distributing US aid, during which small groups of government-backed protesters met him with abuse. He is now believed to be heading to Rome for discussions with the Vatican, increasingly a force on the island.

A spokeswoman for the embassy said they regularly meet with diplomatic colleagues, but “We of course do not discuss the details of our meetings.”

The consequences of the US oil blockade have arrived faster than anyone expected, adding to diplomats’ concerns. All three airlines flying tourists into Cuba from Canada suspended their services this week due to a lack of aviation fuel on the island. Two Russian airlines followed. All five carriers have begun the process of repatriating travellers.

Three-quarters of a million Canadians visited Cuba in 2025, by far the largest group. Russians are the third most numerous category of visitors, after Cuban expatriates. On Wednesday, the UK Foreign Office adjusted its travel advice to recommend only essential travel to the island.

As the oil blockade’s crippling effect on the Cuban government’s ability to earn foreign exchange takes hold, Cubans outside the diplomatic enclaves have begun preparing for life without fuel. “It is starting to feel like the 1962 missile crisis,” said one. “The sun was shining then too, and people went about their business, under a cloud of anxiety.”

Cuba’s government has already shut universities, secondary schools and non-essential state offices and pulled back on public transport in order to preserve resources.

Adrian Rodriguez Suárez has been studying nuclear physics at Havana University. The 22-year-old is from Holguín, a city in Cuba’s east, but lives in student accommodation in East Havana. He has been told to head home to continue his studies by distance learning.

“We heard the news on Thursday and since then, those who can have left,” he said. “Many are using their own means to get home. What worries me is the situation in my province. Although I like the idea of returning to my family, studying is going to be difficult. Outside Havana the electricity availability drops a lot.”

Others have been taking to social media to express their worries. One Facebook user wrote: “I’m getting married in March and I was just advised that the weddings for that month will be cancelled. Does anyone have information?”

Others try to help. “People with chemotherapy, dialysis and emergencies at Calixto hospital [in Havana] travel free,” posted a motorcycle taxi driver.

Then there are those leaning into the situation. A man in La Lisa neighbourhood in Havana is making cast aluminium and galvanised zinc burners for people to cook over wood. At $8 for a single burner and $15 for a double, his tools are proving popular.

“My mother is going crazy with this cooking on charcoal,” said a woman in the rural mid-Cuban town of Sancti Spíritus, who then asked to remain anonymous because otherwise she would have to “make a will to bequeath the charcoal stove to my daughter as her only inheritance”.

Meanwhile, diplomats have been making plans to leave if the situation quickly deteriorates. “What is the point of us being here if we can’t work?” asked one. “We’re prepared, vigilant, and hoping common sense keeps winning a few rounds,” said another.

In the centre of Havana, hotspots that have made the city one of the world’s most loved tourist destinations are falling quiet. Yarini is one of the hippest rooftop bars, named after a famously anti-American pimp of the early 1900s.

Usually it seethes, but on a warm weekday night, only two tables were occupied. Neither of the groups turned out to be local people or regular tourists. Instead they were war correspondents taking a break from winter in Ukraine, in the hope of covering the fall of one of the world’s last communist states.

Additional reporting by Eileen Sosin