“The sum of the different types of fuel: crude oil, fuel oil, of which we have absolutely none; diesel, of which we have absolutely none – I am being repetitive – the only thing we have is gas from our wells, where production has grown,” Vicente de la O Levy said.

The island nation has been suffering extensive blackouts as a result of the U.S. blockade aiming to induce regime change in Havana. The U.S. has offered to provide $100 million in what it called humanitarian aid, but only if “meaningful reforms to Cuba’s communist system” are implemented.

“The decision rests with the Cuban regime to accept our offer of assistance or deny critical life-saving aid and ultimately be accountable to the Cuban people for standing in the way of critical assistance,” the U.S. State Department said in a statement this week.

Earlier in the year, Russia sent two tankers to Cuba, one with crude oil and the other with diesel, which helped alleviate the severe energy shortages on the blockaded island. The vessels reached the Cuban coast despite the U.S. blockade, with President Trump acknowledging Cuba needed relief.

More recently, Bloomberg reported that another Russian tanker was stalling about 1,000 miles from the Cuban coast. The vessel is under U.S. sanctions, the publication noted, and has been idling in open sea since mid-April.

Cuba’s energy crisis is already severe and about to become even more severe, as the weather gets hotter and demand for air-conditioning surges in the summer months. Meanwhile, the Barents Observer reported that the first tanker that delivered crude to Cuba had loaded another cargo at the northern port of Murmansk, adding that it was not immediately clear whether it would set off for Cuba again.