The US government has blocked a Cuban
team from entering the inaugural World Baseball Classic in March.
It has used laws in place since the US economic embargo against Cuba began 40 years ago to stop Cubans from gaining financially from their participation.
The US Treasury Department told event organisers it would be against the law to include a team from Cuba.
A Treasury spokeswoman said: "The Cuba embargo prohibits deals in which Cuba or Cuban nationals have an interest."
The decision is seen as a blow to advocates of easing the embargo, who saw the tournament as an opportunity to foster contacts between Americans
The World Baseball Classic will take place from 3-20 March in the United States, Puerto Rico and Japan.
The Cuban national team was cleared to take part by Cuban President Fidel Castro last month.
It would have played all of its games in Puerto Rico, first against Panama, then the Netherlands and after that Puerto Rico itself.