Washington DC - US Secretary of State Marco Rubio has held secret talks with a descendant of Cuba's communist Castro leadership as he intensifies pressure on the island, a report said.

Axios, quoting unnamed sources, said Rubio has been speaking with Raul Guillermo Rodriguez, the grandson of former leader Raul Castro, who succeeded his brother Fidel Castro.

The news outlet said that the younger Castro (41) was seen as a modernizer who valued a better relationship with the US.

Axios said that the contacts did not go through normal Cuban government channels and were "discussions about the future" rather than negotiations.

Cats Tortoise bestie? Cat owner is shocked to see where her missing kitty turns up!

The State Department and the Cuban embassy in Washington did not immediately respond to requests for comment.

Rubio, a Cuban-American former senator whose parents opposed Fidel Castro's 1959 revolution, is a vociferous opponent of Havana's communists and has long called for regime change.

Cuba is facing growing economic pressure after President Donald Trump ordered an attack on Venezuela that removed leader Nicolas Maduro, a close ally of Havana.

Under US pressure, Venezuela has cut off its vital oil shipments to Cuba, and Trump has threatened sanctions on other countries that sell energy to Havana.

Trump said Monday that Cuba has become "a failed nation" and called for Havana to make a deal with the US.