U.S. President Donald Trump said he has “no problem” with a Russian crude tanker delivering fuel to Cuba, appearing to reverse course over his administration’s oil blockade as the island grapples with a deepening energy crisis.

Speaking to reporters aboard Air Force One on Sunday, Trump said: “If a country wants to send some oil into Cuba right now, I have no problem with that, whether it’s Russia or not.”

His comments come as a Russian-flagged oil tanker, the sanctioned Anatoly Kolodkin, makes its way to Cuba carrying an estimated 730,000 barrels of crude oil.

The tanker is reportedly expected to reach port on Monday and is seen as something of a lifeline to the Caribbean nation, which is facing its biggest test since the collapse of the Soviet Union.

Cuba had been heavily dependent on oil supplies from Venezuela, but it has effectively been cut off since early January when the U.S. launched an extraordinary military operation to depose Venezuelan President Nicolás Maduro.

The Trump administration subsequently threatened to impose tariffs on any country that sent crude to Cuba, prompting the likes of Mexico to halt shipments. The Kremlin has previously shrugged off Trump’s tariff threats, pointing out that Washington and Moscow “don’t have much trade right now.”

Cuba’s President Miguel Díaz-Canel said last week that the island hadn’t received oil shipments in more than three months. The communist-run country, which has said it is holding talks with the U.S., has sought to dramatically increase its solar power generation amid the ongoing fuel shortage.

The island of roughly 10 million people has faced a series of power blackouts in recent weeks and the United Nations has warned that Cuban hospitals have been struggling to maintain emergency and intensive care services.

“Cuba is finished, they have a bad regime and they have very bad and corrupt leadership and whether or not they get a boat of oil it’s not going to matter,” Trump said Sunday.

“I prefer letting it in, whether it’s Russia or anybody else, because the people need heat and cooling and all of the other things that you need,” he added.

The Cuban government said international airlines can no longer refuel there due to fuel shortages after U.S. President Donald Trump threatened tariffs on any country that supplies the communist country with oil.

The island nation’s leadership said Sunday that Cuba will run out of aviation fuel from Monday, likely disrupting operations airlines operating there, according to EFE news agency, citing two sources.

The kerosene shortage is expected to persist for the next month, with all of Cuba’s international airports affected.

Cuba’s Foreign Ministry and the Cuban Embassy in London did not immediately respond to a CNBC request for comment.

Trump, in an executive order issued at the end of January, said the Cuban government constituted “an unusual and extraordinary threat,” which required a national emergency declaration.

The U.S. president said that Cuba’s ties to countries including China, Russia and Iran, human rights violations and communist leadership destabilize the region “through migration and violence.”

As part of the announcement, Trump said U.S. tariffs may target countries that provides any oil to Cuba, whether directly or indirectly.

The Trump administration has sought to tighten the U.S. chokehold on Cuba since Jan. 3, when it conducted an audacious military operation to depose Venezuelan President Nicolás Maduro, a long-time ally of Cuba’s government.

The plan reportedly includes restrictions on fuel sales, the closure of some tourist establishments, shortening school days, and a reduction of the working week in state-owned companies to four days, from Monday to Thursday.

Russia, which holds friendly ties with Cuba, said Monday that Havana’s fuel situation was “truly critical” and that U.S. attempts to further pressure the country were causing numerous problems.

“The situation in Cuba is truly critical. We know this. We are in intensive contact with our Cuban friends through diplomatic and other channels. Indeed, let’s say the U.S.’s stranglehold is causing many difficulties for the country,” Kremlin Spokesperson Dmitry Peskov told reporters on Monday, according to state news outlet RIA Novosti.

Cuba’s Foreign Minister Bruno Rodríguez Parrilla previously said the country’s leadership condemned Washington’s tariff threats in the “strongest possible terms.”

In a statement posted on Jan. 30, Parrilla also accused the U.S. government of resorting to “blackmail and coercion in an attempt to make other countries to join its universally condemned blockade policy against Cuba.”

Mexican President Claudia Sheinbaum said last week that her government would aim to send humanitarian aid to Cuba from Monday, adding that the country is working to find a diplomatic solution to resume oil shipments to the Caribbean island.

Mexico had paused shipments of crude and refined products to Cuba amid pressure from the Trump administration.