The White House said Monday it has not changed U.S. policy toward Cuba, even as it allowed a sanctioned Russian tanker to deliver fuel to the island for humanitarian reasons, saying such decisions would be handled on a case-by-case basis.

"This is not a policy change. There has not been a formal change in sanctions policy," White House press secretary Karoline Leavitt told reporters. "As the president said last night, we allowed this ship to reach Cuba in order to provide humanitarian needs to the Cuban people."

The U.S. still reserves the right to seize vessels, if legally applicable, that are headed toward Cuba and violate U.S. sanctions policy, she added.

The U.S. cut off Venezuela's oil exports to Cuba after toppling Venezuelan President Nicolas Maduro on Jan. 3, and Trump threatened to slap punishing tariffs on any other country that sent crude to Cuba.

But Trump on Sunday signaled he was reversing course and expressed sympathy for the Cuban people's need for energy.

"If a country wants to send some oil into Cuba right now, I have no problem with that, whether it’s Russia or not," he said.

Cuba has not received an oil tanker in three months, according to President Miguel Diaz-Canel, exacerbating an energy crisis that has led to strict gasoline rationing and a series of blackouts across the country of 10 million people.

Cuban health officials say the crisis has increased the mortality risk for Cuban cancer patients, especially children.

Russia said on Monday that an oil tanker carrying 100,000 metric tons of crude oil had arrived in Cuba.