Russia has repeatedly supplied oil to Cuba in recent years, and will continue to do so, Russian Ambassador to Cuba Viktor Coronelli said in an interview.

"We assume that this practice will continue," he said.

U.S. President Donald Trump on Sunday said the United States had begun talks with "the highest people in Cuba," days after declaring Cuba "an unusual and extraordinary threat" to U.S. national security and threatening tariffs on the U.S.-bound exports of any nation that sends oil to the island.

The U.S. has moved to block all oil from reaching Cuba, including that from ally Venezuela, pushing up prices for food and transportation and prompting severe fuel shortages and hours of blackouts, even in the capital Havana.