Former Brazilian president Jair Bolsonaro was taken into federal police custody on Saturday before a planned supporters' vigil near his home, ending months of house arrest as he appeals a Supreme Court conviction for plotting a coup.

Bolsonaro's attorney Celso Vilardi confirmed the detention but did not cite a reason. A federal police representative said Bolsonaro underwent custody intake examinations in Brasilia early on Saturday.

Supreme Court Justice Alexandre de Moraes ordered the detention in a court decision, seen by Reuters, citing the risk of encamped supporters hampering police monitoring of Bolsonaro's house arrest. He also noted evidence of tampering with the ex-president's ankle monitor the night before.

JUDGE CITES ESCAPE RISK

"The tumult caused by an illegal gathering of the convict's supporters has a strong chance of putting at risk the house arrest and other precautionary measures, allowing for his eventual escape," wrote Supreme Court Justice Alexandre de Moraes in his decision ordering the detention on Saturday.

The judge cited evidence that Bolsonaro had previously considered seeking asylum in the Argentine embassy in Brasilia. One of his sons and other close allies have fled Brazil to avoid the reach of the country's courts, Moraes noted in his decision.

Another Bolsonaro attorney declined to comment immediately on the basis of the court decision.

The right-wing former leader was sentenced in September to 27 years and three months in prison for plotting a coup after losing the 2022 presidential election to leftist Luiz Inacio Lula da Silva.

Bolsonaro was identified as the leader and main beneficiary of a scheme to prevent Lula from taking office in 2023. However, the courts have not yet issued a final arrest order in that case, as Bolsonaro has not exhausted the appeals process.

For more than 100 days, Bolsonaro has been under house arrest for violating precautionary measures in a separate case over allegedly courting U.S. interference to halt the criminal case against him.

U.S. President Donald Trump, who was friendly with Bolsonaro when they were both in office, has called the case a "witch hunt". He imposed sanctions on Moraes, the justice overseeing it, and a 50% tariff on U.S. imports of several Brazilian goods, which he began to roll back this month.

'COME FIGHT WITH US', SAYS BOLSONARO'S SON

While under house arrest, Bolsonaro was barred from using social media, but received visits from political allies.

His son, Senator Flavio Bolsonaro, put out a call on social media for supporters to gather outside his father's condominium in Brasilia on Saturday evening.

"I invite you to come fight with us," the senator said in a video posted online. "With your strength, the strength of the people, we'll fight back and rescue Brazil."

If his appeals are unsuccessful, Bolsonaro's defense is expected to seek permission for him to serve his nearly three-decade sentence under house arrest, citing several health issues.

The former president, who was stabbed in the abdomen during a 2018 campaign event, has a history of hospitalizations and surgeries related to the attack.

Bolsonaro had previously been banned from running for office until 2030 after Brazil's electoral court found him guilty of abusing his office during his 2022 re-election campaign.