CARACAS, Venezuela -- A newly installed constitutional assembly ousted Venezuela's defiant chief prosecutor Saturday -- a sign that President Nicolas Maduro's embattled government intends to move swiftly against critics and consolidate power amid a fast-moving political crisis.

Cries of "traitor" and "justice has arrived" erupted from the 545 pro-government delegates during the unanimous vote to remove Luisa Ortega from her post as the nation's top law enforcement official and replace her with a staunch government supporter.

They said they were acting in response to a ruling by the government-stacked Supreme Court, which had also been considering a request to sanction Ortega.

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Earlier Saturday, Ortega, a longtime loyalist who broke with the socialist government in April, said she was pushed and barred from entering her office by dozens of national guardsmen in riot gear who took control of the entrance to the building.

She alleged that authorities were desperate to get their hands on sensitive dossiers containing information on dirty dealings by high-level officials, including details about millions of dollars in bribes paid by Brazilian construction giant Odebrecht.

"Do you know what they want to achieve with this? They want to hide the corruption and violation of human rights taking place in Venezuela that I will continue to denounce," Ortega told journalists outside the building.

Assembly delegates voted to replace her with Tarek William Saab, who was recently sanctioned by the Trump administration for failing to protect protesters from abuses in his role as the nation's top human rights official.

Members of the all-powerful constitutional assembly had pledged in their first meeting to move quickly against Maduro's opponents.

"Don't think we're going to wait weeks, months or years," former Foreign Minister Delcy Rodriguez said Friday after she was unanimously chosen to lead the assembly. "Tomorrow we start to act. The violent fascists, those who wage economic war on the people, those who wage psychological war, justice is coming for you."

The constitutional assembly was seated despite strong criticism from the United States, other countries and the Venezuelan opposition, which fear the it will be a tool for imposing dictatorship. Supporters say it will pacify a country rocked by violent protests.

Its installation is virtually certain to intensify a political crisis that has brought four months of protests in which at least 120 people have died and hundreds more have been jailed.

Maduro vows the assembly will strip opposition lawmakers of their constitutional immunity from prosecution, while members of congress say they will only be removed by force.

But the opposition is struggling to regain its footing in the face of the government's strong-arm tactics and the re-emergence of old, internal divisions. Several opposition activists have been jailed in recent days, others are rumored to be seeking exile and one leader has broken ranks from the opposition alliance to say his party will field candidates in regional elections despite widespread mistrust of Venezuela's electoral system.

In a sign of its cowered and demoralized state, only a few hundred demonstrators showed up for a Friday protest against the constitutional assembly, one of the smallest turnouts in months. Those who did turn out said fear of arrest -- rights groups claim there are more than 600 "political prisoners" jailed during the protests -- may be keeping people at home but urged Venezuelans to remain mobilized.

"This is what the constitutional assembly will bring: more repression," opposition lawmaker Miguel Pizarro said.

Maduro accuses his opponents of using violence and argues that the constitutional assembly is the best way to restore peace.

An increasing number of foreign governments have refused to recognize the constitutional assembly, further isolating Maduro's government on the international stage.

President Trump's top national security adviser, General H.R. McMaster, said he doesn't see a military intervention in Venezuela as likely -- even as he's calling on nations to help "rescue" the country from "authoritarian dictatorship."

McMaster cites the historical resentment in Latin America over the long history of U.S. military interventions in the region. He said he doesn't want to give Maduro any added ammunition to blame "Yankees" for Venezuela's political crisis.

"You've seen Maduro have some lame attempts to try to do that already," McMaster said in an interview on MSNBC that aired Saturday.

He added that it's "important for us to place responsibility for this catastrophe on Maduro's shoulders. He is the one who has caused it, and he's the one who's perpetuating it."

Also Saturday, the South American trade bloc Mercosur moved to suspend Venezuela for failing to follow democratic norms.

Venezuela was previously suspended in December for failing to uphold commitments it made when it joined the group in 2012. The new decision will make it harder for the country to return to good standing since the new suspension can be lifted only when the bloc is satisfied that Venezuela has restored democratic order.

"Today in Venezuela there is no democracy," Argentine Foreign Minister Jorge Faurie said. "Essentially what Mercosur is saying is: Without democracy, no, you cannot be a part of Mercosur."

The opposition boycotted the July 30 election for the constitutional assembly, saying the rules were rigged to further entrench Maduro's "dictatorship."

The results have come under mounting scrutiny after the international company that provided the electronic voting machines said that "without any doubt" the official turnout had been tampered with -- a charge dismissed by Maduro and the National Electoral Council.

The constitutional assembly is made up of delegates from an array of pro-government sectors such as trade unionists, students and even representatives of Venezuelans with physical disabilities. But the agenda is expected to be set by bigger-name loyalists, including Maduro's wife, son and several Cabinet ministers who resigned to join the body.

It will have sweeping powers to upend institutions and in theory could even remove Maduro, a fact held up by government supporters as a sign of its independence from the government.