The US has cancelled an agreement that allowed Cuban baseball stars to sign with American teams.
The deal meant players no longer had to defect from communist Cuba to join Major League Baseball (MLB) teams.
Signed in December, it enabled players to reach the US without resorting to human traffickers.
US Secretary of State Mike Pompeo said the decision to withdraw was part of efforts to pressure Cuba over its support for the Venezuelan government.
The US is backing opposition politician Juan Guaidó, who has declared himself Venezuela's interim leader in a bid to unseat President Nicolás Maduro.
The policy backtrack has been criticised on social media by Cuban President Miguel Díaz-Canel, who called it "a cynical, cruel and gratuitous act".
Negotiations over the deal began under President Barack Obama to ease relations with Cuba, which traditionally produces some of the world's best baseball players.
As part of the deal, Cuban players over age 25 who played in Cuban leagues for six years were free to leave and sign with MLB teams.
The Cuban Baseball Federation (FCB) had recently given permission for its first group of athletes to begin playing in the US this year.
A state department official, however, told the BBC that "based on additional information that has come to light", the US now considers the FCB as part of Cuba's government. As such, it is subject to ongoing embargoes.
Last Friday, the US Treasury sent MLB a letter - seen by the BBC - saying payments to the FCB were now considered "payments to the Cuban government".
MLB told the BBC it stood by "the goal of the agreement, which is to end the human trafficking of baseball players from Cuba".
The BBC understands that MLB has requested a meeting with the US government but has not had a reply so far.
In a statement, the FCB said the announcement only defended "political interests, without caring for the welfare and tranquillity of Cubans".
Before the deal, Cuban players who wanted to sign with US teams had to leave the country illegally.
For decades, as a result, many Cuban players suffered kidnapping and extortion from traffickers - some with ties to drug cartels - on their journey to America.
Among those currently playing in the MLB are Aroldis Chapman, who pitches for the New York Yankees.
"I just feel bad for those young ballplayers who are probably not going to have the same chance to play here," Mr Chapman told ESPN.
"Now the opportunity's being taken away, and some of them still want to play here at this level. And, unfortunately, they might find themselves making difficult decisions in how to get here."