A Brazilian Supreme Court justice placed former President Jair Bolsonaro under house arrest Monday for violating a social media ban – an explosive move that deepens the high-stakes clash between the judiciary and the former leader, who is accused of plotting a coup to overturn the 2022 election.

Bolsonaro, 70, is on trial for allegedly attempting to cling to power after losing to President Luiz Inacio Lula da Silva. As part of the proceedings, he is barred from using social media, and others are prohibited from broadcasting his statements.

That order was defied Sunday when allies shared footage of Bolsonaro speaking to his son Flavio during a rally in Rio de Janeiro.

Justice Alexandre de Moraes swiftly condemned the breach, accusing Bolsonaro of trying to "treat the judiciary like a fool” and vowing not to be swayed by "political and economic power.”

Meanwhile, U.S. President Donald Trump criticized the case, calling it a politically motivated "witch hunt” and threatening punishing tariffs on Brazil, Latin America’s largest economy, in response.

Citing Bolsonaro’s "repeated failure” to comply with court-imposed restrictions, Moraes placed him under house arrest at his residence in the capital, Brasília.

The justice also barred Bolsonaro – who served as president from 2019 to 2022 – from receiving visitors other than his lawyers and from using mobile phones. Moraes warned that any further violations would result in pretrial detention.

Police said several mobile phones were seized at Bolsonaro’s home on Monday.

The U.S. State Department’s Bureau of Western Hemisphere Affairs condemned the new restrictions Monday night in a post on X.

"Minister Alexandre de Moraes, already sanctioned by the United States for human rights violations, continues to use Brazilian institutions to silence the opposition and threaten democracy,” the bureau wrote. "Let Bolsonaro speak!”

U.S. officials added they would "hold accountable all those who collaborate with or facilitate sanctioned conduct.”

The post was re-shared by Bolsonaro’s son, Eduardo Bolsonaro, a politician who had lobbied Washington to take punitive action against Brazil over the case.

In a separate post, he wrote: "Brazil is no longer a democracy.” He also called Moraes, who has cast himself as a defender of democracy in the face of far-right extremism, an "out-of-control psychopath.”

Last month, Moraes ordered Bolsonaro to wear an ankle monitor and imposed the social media ban.

Trump responded by imposing sanctions on Moraes, banning him from the United States and freezing his U.S. assets.

At rallies held Sunday in Rio de Janeiro, Brasília and Sao Paulo, some Bolsonaro supporters waved U.S. flags or held signs reading "Thank you Trump.”

Bolsonaro did not attend the rallies, having been ordered by the court to remain at home during nights and weekends throughout the trial.

Prosecutors allege Bolsonaro and seven co-defendants conspired to overturn the 2022 election result – a plan they say only failed because the military refused to support it.

If convicted, Bolsonaro could face up to 40 years in prison. The trial is expected to conclude in the coming weeks.

In January 2023, Bolsonaro supporters stormed Brazil’s Congress after Lula’s inauguration, ransacking the chambers and clashing with police – scenes that echoed the Jan. 6, 2021, attack on the U.S. Capitol by Trump supporters.

Although barred from running for office, Bolsonaro hopes to mount a Trump-style comeback in Brazil’s 2026 presidential election.

Lula, 79, has said he may seek a fourth term, health permitting. Last year, he was hospitalized with a brain hemorrhage caused by a bathroom fall.