U.S. Secretary of State Marco Rubio on Wednesday took steps to revoke or restrict visas for some African, Caribbean and Brazilian officials who Washington alleges have ties to a Cuban program that sends medical workers overseas.

Axar.az reports, citing Reuters, the State Department revoked the visas of Brazilian Ministry of Health official Mozart Julio Tabosa Sales and former Pan American Health Organization official Alberto Kleiman, Rubio said in a statement.

Rubio did not name other officials who were affected but said they were from Africa, Cuba and Grenada.

The Cuban government has blasted U.S. efforts to stop the medical missions, calling them a cynical excuse to go after its foreign currency earnings.

Rubio labeled the Cuban program as one where "medical professionals are 'rented' by other countries at high prices and most of the revenue is kept by the Cuban authorities." He said it enriches Cuban officials and deprives Cuban people of essential medical care.

Washington will act "to bring an end to such forced labor," Rubio said, urging governments to pay doctors directly for their services.

In announcing restrictions on Brazil and ex-PAHO officials, Rubio accused the branch of the World Health Organization covering Caribbean, Central and South America of acting as an intermediary to implement the program without following Brazilian constitutional requirements, and dodging U.S. sanctions.