Eduardo Bolsonaro, a Brazilian congressman and a son of former President Jair Bolsonaro, said on Tuesday that he would seek political asylum in the United States, claiming he is the target of persecution for defending the right-wing movement embodied by his father.

The third-oldest son of the former Brazilian president has been in the United States since late February, just as Brazil’s Supreme Court began weighing whether to seize his passport over accusations that he tried to interfere in the case involving his father’s alleged role in a coup plot after the older man lost the 2022 election.

Mr. Bolsonaro, 40, said in a video posted on social media that he intended to remain in the United States and step back from his role as a federal lawmaker. Mr. Bolsonaro has close ties with the Trump family and has visited President Trump at Mar-a-Lago, his Florida home and club.

Mr. Bolsonaro also denounced a Supreme Court justice, Alexandre de Moraes, for targeting him. Justice de Moraes has been overseeing the criminal case against Jair Bolsonaro.

“If Alexandre de Moraes wants to seize my passport or even arrest me so that I can no longer report his crimes in the United States, then this is precisely where I will stay and work harder than ever,” the younger Mr. Bolsonaro said in the video.

After the video was published, Brazil’s top prosecutor said he was not seeking Mr. Bolsonaro’s passport.

Mr. Bolsonaro did not make clear when he would request asylum. The White House did not immediately respond to a request for comment.

The announcement by Mr. Bolsonaro comes days before Brazil’s Supreme Court is to decide whether to put his father on trial on charges that he oversaw a vast plot to subvert the nation’s democracy after the 2022 election, which he lost.

Brazilian prosecutors say the plot included plans to annul the vote, disband courts and assassinate President Luiz Inácio Lula da Silva, who won the vote. The older Mr. Bolsonaro has called the charges politically motivated.

Eduardo Bolsonaro said his father ran the risk of being “unjustly imprisoned” by the Supreme Court, which has long been seen as an enemy by Brazil’s conservative movement, and drew a parallel between his father and Mr. Trump’s own legal troubles.

“I have no doubt that our enemies’ plan is to incarcerate him, to assassinate him in prison or leave him there forever, just as would have happened with Donald Trump if he had not been re-elected in 2024,” he said in the video.

Mr. Trump’s media company has sued Justice Moraes, accusing him of illegally censoring right-wing voices on social media.