Richardson arrived in Cuba last week amid reports that he had been invited by the Cuban government to discuss the release of Alan Gross, a 62-year-old government contractor detained in Cuba since 2009.
The former U.N. ambassador told The Washington Post his diplomatic efforts were rebuffed. "My sense is, there are some elements in their government that don't want to improve relations with the U.S.," Richardson said Sunday in a telephone interview with The Washington Post.
Richardson, who had said he would not leave the country until he was allowed to see Gross, reportedly left Cuba Wednesday, The Miami Herald reported.
CNN said the Cuban government alleges Richardson had not been invited to discuss the Gross case.