Loyalists of President Nicolás Maduro in Venezuela’s newly created super congress moved to consolidate government power Saturday, stripping the independent chief prosecutor of her job and cordoning off her headquarters in a move signaling a swiftly widening crackdown on political dissent.

The new body, elected last Sunday in a vote decried internationally as a power grab, was installed Friday, with its leaders vowing to back Maduro’s calls to move against political opponents. Those threats translated into fast action, with hundreds of troops surrounding chief prosecutor Luisa Ortega Díaz’s office at dawn. Ortega Díaz was the most prominent senior administration official in Venezuela who is a vocal critic of the Maduro government.

The move appeared to signal a dangerous new phase in Venezuela’s break with democracy, reinforcing fears about Maduro using the new National Constituent Assembly (ANC), to rubber-stamp a fresh campaign against opponents. In addition to firing Ortega Díaz, the assembly ordered her not to leave the country and replaced her with a Maduro loyalist.

“Ortega Díaz didn’t give the impression of being objective in her duties,” the assembly’s second vice president, Isaías Rodríguez, said. “ This decision is not news. Everyone knew it was coming long before the ANC was installed.”

In a communique issued by the Public Ministry, Ortega Díaz denounced the decision to remove her from the position of attorney general of the republic as a violation of the constitution.

“We are just a tiny sample of what comes to anyone who dares to oppose the totalitarian way of governing,” she said. “I will continue fighting for Venezuelans, for their liberties and rights, until my last breath.”

Ortega Díaz broke with Maduro in March and has strongly criticized the government’s actions against pro-democracy demonstrators. More than 100 have died and thousands have been detained in four months of street protests.

Ortega Díaz said that she was not inside her headquarters in central Caracas when troops surrounded the building but that members of her staff were trapped inside.

“My office has been taken by public security forces, including national guards and policemen, between 400 and 500” troops, she said. “We still don’t know how many of our employees are inside. They’re not permitting us to go in, or anyone to go out.”

In an interview with The Washington Post, she denounced the creation of the new Constituent Assembly — members of which include Maduro’s wife and son — as “the birth of a dictatorship.”

Speaking before the assembly’s action, she said: “If they remove me, I’ll keep fighting for human rights and for democracy. I can’t permit my country to become a dictatorship.”

On Friday, Ortega Díaz had challenged the legality of the Constituent Assembly, a body of 545 Maduro loyalists elected in a vote that the firm that supplies balloting technology to Venezuela called grossly manipulated. Opponents, who boycotted the election, describe the new body’s creation as a move to solidify Maduro’s autocratic rule and create a Cuban-style dictatorship. Maduro has said it would give more representation to average citizens. Its members range from slum dwellers and fisherman to top government officials.

The assembly replaced Ortega Díaz with Maduro’s ombudsman, Tarek William Saab. The proclamation brought rousing applause and shouts of support from the chamber.

Before the vote to remove Ortega Díaz, the assembly heard a statement from the president of the pro-government supreme court. It informed the body of the court’s decision to suspend Ortega Díaz pending an investigation. But the new assembly went further, striping her of her job and barring her from leaving the country.

Diosdado Cabello, a leading member of the new assembly and a powerful figure in Maduro’s inner circle, made the motion to remove her instead of suspending her. The vote included a pledge to “urgently restructure” the independent office.

The assembly’s action brought the indefinite suspension of Venezuela from the South American trade bloc Mercosur, a decision announced in Sao Paulo’s city hall by the foreign ministers of Argentina, Paraguay, Uruguay and Brazil.

Brazilian Foreign Minister Aloysio Nunes said that to avoid worsening the humanitarian crisis in Venezuela, the suspension will not affect trade or migration policies.

Maduro responded in an interview with Argentina’s Radio Rebelde that Venezuela will never be removed from Mercosur. “Venezuela has met more Mercosur standards than the founding countries,” he said.

Ortega Díaz said she was being targeted for calling out the government.

“The attack comes because of the attitude I have assumed in defense of human rights and democracy,” she said. “Because the government has committed serious violations, including arbitrary detentions, torture, cruel [and] inhumane treatment, the use of military justice to judge civilians and the planting of evidence.”

Ortega Díaz represents a political camp in Venezuela of leftist populists who have broken with Maduro. She was, and still is, a Chavista — a backer of the late president, Hugo Chávez, who anointed Maduro as his successor before his death in 2013.

For years Ortega Díaz backed Maduro, supporting legal action against leading dissident Leopoldo López, who was jailed in 2014. She broke with the government, however, after increasing human rights and democratic abuses. She has said that her daughter and grandson were kidnapped and held for three days in what she considered to be government pressure tactics.

The opposition leaders who have led the most recent uprising — four months of street protests — once saw her as an enemy. But they have embraced her willingness to condemn and investigate a major surge in fatalities and arrests of dissidents. On Saturday, a group of top opposition officials went to the prosecutor’s office in a show of support.

“All of our support to the Chief Prosecutor Luisa Ortega Díaz,” tweeted Julio Borges, head of the National Assembly, whose members were elected in 2015 but have now been pushed aside by the Constituent Assembly. “Together, in the defense of the constitution and democracy, we will overcome the dictatorship.”

A month ago, the supreme court announced it would conduct a preliminary hearing on whether to suspend Ortega Díaz. She refused to attend, and the court froze her assets and prohibited her from leaving the country.

On Friday, the Inter-American Commission on Human Rights, part of the Organization of American States, warned Venezuela not to target Ortega Díaz and her family.

¨They’re in a grave and urgent situation and their rights and integrity face imminent irreparable risk,” the statement said. It cited comments by high-ranking officials suggesting that Ortega Díaz was backing “terrorist” acts and government betrayal.

Gabriela Ramirez, a former national ombudsman on human rights who also recently broke with Maduro, said the move against the chief prosecutor amounts to the start of a new campaign against opponents. She said she fears the new assembly will give Maduro legal cover to act more forcefully.

“This is the establishment, through the naked force of the state, of a parallel justice system,” Ramirez said.