Secretary of State Marco Rubio has been holding secret talks with the grandson of Cuba's former leader Raul Castro, Axios reported on Wednesday, citing people familiar with the matter.

"I wouldn't call these 'negotiations' as much as 'discussions' about the future," Axios said, citing a senior Trump administration official while referring to the talks between Rubio and Raul Guillermo Rodriguez Castro, the grandson of Raul Castro.

Reuters could not immediately verify the report. The U.S. State Department did not immediately respond to a request for comment.