Cuba has announced it will not be sending a team of boxers to the World Boxing Championships in Chicago in October to avoid attempted defections.
Lara (L) and Rigondeaux may be banned from competing for Cuba
Cuba's boxing federation said it would not expose its boxers to "traffickers", who would attempt to lure them away with offers of professional contracts.
Cuba's boxers are traditionally world leaders in amateur boxing, but are forbidden to box professionally there.
In July, two Cuban boxers abandoned their team at an event in Brazil.
Guillermo Rigondeaux and Erislandy Lara, both amateur world champions, were deported from Brazil to Cuba earlier this month after their apparent attempt to defect during the Pan-American Games in Rio de Janeiro.
'Patriotism shall prevail'
Cuban leader Fidel Castro threatened earlier this month to pull his country's boxing team out of the championship, which is a qualifying event for the 2008 Beijing Olympics.
Cuba would not sacrifice its honour for Olympic gold medals, Mr Castro wrote in the state-run Granma newspaper.
Cuban sports officials were considering all options to prevent defections, Mr Castro said, including sending an alternative team to Chicago in October, or not sending any boxers at all.
"The morale and patriotism of [Cuba's] athletes shall prevail above all else," the 80-year-old leader wrote.
Sporting success is a matter of national pride in the communist country, says the BBC's Michael Voss in Havana.
Boxing is one of its specialities and it has produced a long line of Olympic champions.
But Cuban athletes have in the past used overseas sporting events to defect, often to lucrative professional contracts, our correspondent says.
'Point of no return'
In the most recent case, Rigondeaux, a double Olympic and amateur world bantamweight champion, and Lara, a world amateur welterweight champion, failed to show up for their fights in Rio despite being favourites to win gold.
Brazilian police detained them for overstaying their visas.
German sports company Arena said it had signed a contract with the boxers.
But an Arena spokesman told Brazilian media the boxers had later changed their minds about signing out of fear for their families' safety back in Cuba.
Mr Castro suggested they would not be allowed to compete for Cuba, saying they had reached a "point of no return" in Cuba's boxing team.
The whereabouts of two other Cubans - handball player Rafael Dacosta and gym trainer Lazaro Lamelas - who also disappeared during the Pan-American Games are not known.