A new assembly loyal to President Nicolas Maduro on Saturday fired the country's attorney general, Luisa Ortega, one of his most vociferous critics, triggering a firestorm of condemnation from the US and Latin American nations.
"The United States condemns (the) illegal removal" of Ortega, US State Department spokeswoman Heather Nauert tweeted, adding the move was aimed at tightening the "authoritarian dictatorship of (the) Maduro regime."
Colombia, Chile, Guatemala, Mexico, Panama, and Peru equally slammed the decision, made by the Constituent Assembly as its very first order of business a week after it was elected in a vote marred by violence and fraud allegations.
The assembly also said Ortega would face trial for "irregularities" from her time in office and was forbidden from leaving the country.
Ortega, who was barred by dozens of soldiers from entering her offices, refused to recognize her sacking, or the assembly's swearing in of Tarek William Saab, the national ombudsman, in her place.
"I am not giving up, Venezuela is not giving up and will not give up against barbarity, illegality, hunger, darkness and death," she said.
Ortega has been a thorn in Maduro's side for months, breaking ranks with him over the legality of the Constituent Assembly.
One of the assembly's most prominent members, Diosdado Cabello, said of the firing: "This is not a personal, political lynching, just carrying out the law."
Ortega's sacking had been widely expected. But its swiftness -- and the fact it was a unanimous vote -- stirred wide unease.
Mercosur suspension
Maduro and his Socialist party have "completely taken hostage" Venezuela's institutions through "an undemocratic mechanism that is utterly dictatorial," the leader of the opposition-controlled legislature, Julio Borges, told reporters.
As Ortega's firing was announced, Argentina, Uruguay, Paraguay and Brazil declared Venezuela was indefinitely suspended from the South American trading bloc Mercosur for its "rupture of the democratic order."
The United States and the office of the head of the Organization of American States, Luis Almargo, endorsed the suspension.
"The countries of the region... must continue to tell the Venezuelan regime that in the Americas, there is no place for dictatorships or for the tyrants that lead them," it said in a statement.
The international onslaught added to US sanctions imposed on Maduro after the Constituent Assembly's election.
Maduro responded in an interview with an Argentine radio station that "Venezuela will not be taken out of Mercosur - never!"
He accused his Argentine counterpart, Mauricio Macri, of trying to impose a "blockade" on Venezuela and US President Donald Trump of wanting to grab the country's vast oil reserves.
Trump's national security advisor, H.R. McMaster, this week ruled out foreign military intervention and said Washington did not want to give Maduro a pretext for blaming the US for his mounting woes.
The United States, the European Union and major Latin American nations have all rejected the Constituent Assembly.
The body's legitimacy was struck a hard blow this week when a British-based firm that supplied the voting technology, Smartmatic, said the turnout figure was "tampered with" and greatly exaggerated.
Supreme powers
The principal task of the Constituent Assembly is to rewrite the constitution, something Maduro promised will resolve Venezuela's troubles.
"We are going to win back peace," the president said.
While working on its mission, the assembly holds supreme powers over all other branches of government.
Initial suggestions were that it would need only six months to complete its work.
But it announced on Saturday that it would stay in place for up to two years - beyond the end of Maduro's term, due to end in 2019.
Its 545 members, all Maduro allies, include the president's wife and son. It is led by Maduro's fiercely loyal former foreign minister, Delcy Rodriguez.
The opposition has vowed to maintain street protests against the assembly.
Four months of demonstrations violently matched by security forces have left at least 125 people dead.
But the rallies grew more muted this week as the assembly took its seats and vowed to go after those seen as inciting street action.
Maduro has around 20 percent public support, according to surveys by the Datanalisis polling firm.
Ordinary Venezuelans are struggling, with food, essentials and medicine scarce, the currency rapidly depreciating, and inflation soaring. Thousands have sought shelter in neighboring countries, particularly Colombia and Brazil.