Camacho was arrested on Wednesday and taken to political capital La Paz, escalating tensions between his wealthy agricultural base in the region of Santa Cruz and the national government.

Civic groups in Santa Cruz are demanding Camacho's immediate release and have called for a general strike on Friday and for highways to be blockaded.

Prosecutors have charged Camacho with "terrorism" and are also investigating allegations including breach of duty, misuse of influence and attacks on the president and high-ranking state dignitaries, Mejillones said.

The charges are connected to the ouster of former leftist President Evo Morales in November 2019. Morales had declared victory in a disputed presidential election that would have given him a fourth straight term but ended up fleeing the country amid fiery protests, some of which were led by Camacho.

More recently, Camacho, who finished third in the 2020 presidential contest, has backed protests in Santa Cruz demanding the national government proceed with a delayed census, which would likely give his region more tax revenues and seats in Congress.

In a statement, Camacho said the accusations against him lacked truth and credibility, and his lawyer Juan Carlos Camacho said he had been "unjustly" detained.

On Thursday, Camacho's Twitter account said that authorities had prevented his lawyers from filing a constitutional recourse to free him. A video attached to the tweet alleged his constitutional rights had been breached and that he had been "kidnapped" and taken illegally to La Paz.

Mejillones said Thursday he had "no knowledge" of the lawyers' allegations of being unable to file the recourse.

The state attorney's office has denied the arrest was either a kidnapping or politically motivated.

UNEASY CALM

Most governments across the region were largely silent on the issue Thursday, though the United States said it was aware of Camacho's arrest and monitoring developments.

"We encourage observance of international norms and reliance on democratic institutions. We urge all parties to resolve this issue peacefully and democratically," said a State Department spokesperson.

Former President Morales said on Wednesday he hoped Camacho's detention would bring justice after three years.

"Luis Fernando Camacho will answer for the coup d'etat that led to robberies, persecutions, arrests and massacres of the de facto government," Morales tweeted.

Former President Carlos Mesa, an ally of Camacho's who ran against Morales in the 2019 election, told Reuters the case stemmed from "a monumental electoral fraud carried out by Evo Morales" and that the terrorism charge "does not make any sense."

Meanwhile, a group of Bolivian lawmakers from Camacho's Creemos party sent a letter to the Inter-American Commission on Human Rights calling for precautionary measures to protect Camacho's "safety and integrity."

There was an uneasy calm Thursday in Santa Cruz, where signs of damage were visible after protests Wednesday ended with the Santa Cruz prosecutor's headquarters set on fire.

Public Works Minister Edgar Montano said on Twitter his house in Santa Cruz had been set on fire and robbed. Two people were arrested in relation to the incident, Montano said, adding that Camacho and his allies would be "responsible for anything that might happen" to him or his family.

The federal prosecutor's office said it would seek the "harshest punishment" possible for those responsible for damage in Santa Cruz.