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" erupted from the stately, neo-classical salon where 545 pro-government delegates voted unanimously 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 banned Ortega from leaving the country and freezing her bank accounts while it weighs criminal charges against her for alleged irregularities.

Ortega, a longtime loyalist who broke with the socialist government in April, refused to recognize the decision and vowed to continue defending the rights of Venezuelans from Maduro's "coup" against the constitution "with my last breath."

'A tiny example of what's coming'

"This is just a tiny example of what's coming for everyone that dares to oppose this totalitarian form of government," Ortega said in the statement she signed as chief prosecutor. "If they're doing this to the chief prosecutor, imagine the helpless state all Venezuelans live in."

Earlier Saturday, Ortega 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.

National guardsmen in riot gear prevent Ortega Diaz, third left, from entering the general prosecutor's office. (Wil Riera/Associated Press)

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

Assembly delegates later swore in as her replacement Ombudsman 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.

'Justice is coming for you'

Members of the all-powerful constitutional assembly had pledged in their first meeting to move quickly against Maduro's opponents and didn't disappoint.

"Don't think we're going to wait weeks, months or years," former Foreign Minister Delcy Rodriguez said Friday after she was 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."

Rechazo asedio al <a href="https://twitter.com/MPvenezolano">@MPvenezolano</a>. Denuncio esta arbitrariedad ante la comunidad nacional e internacional <a href="https://twitter.com/hashtag/5Ag?src=hash">#5Ag</a> <a href="https://t.co/un7QWGBGJ7">pic.twitter.com/un7QWGBGJ7</a> —@lortegadiaz

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.

Smallest protest crowd in months

Maduro also wants the assembly to strip opposition lawmakers of their constitutional immunity from prosecution, saying their constant conspiring to oust him shouldn't be protected.

While members of congress say they will only be removed by force, 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 rumoured 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 distrust of the electoral system.

Venezuela's new chief prosecutor Tarek William Saab attends his appointment ceremony in Caracas on Saturday. (Ueslei Marcelino/Reuters)

In a sign of its cowered, 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.

"We shouldn't think the government is winning," said Julio Borges, president of the opposition-controlled congress, making an emotional plea for Maduro's opponents to remain on the streets and capitalize on the government's increasing international isolation. "The only thing it's doing is destroying itself and committing suicide."

'There is no democracy'

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

On 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."