Venezuelan President Nicolas Maduro has provoked international criticism and enraged his political opponents by pushing for a special assembly to rewrite the troubled South American nation's constitution.

Sunday's election of delegates to the assembly comes after nearly four months of political upheaval that have resulted in more than 100 deaths and left thousands injured and detained.

Bolivarian National Guards detain an anti-government demonstrator during clashes in Caracas, Venezuela, Friday, July 28, 2017, two days before the vote to begin the rewriting of Venezuela's constitution. Protesters say the election of a constitutional assembly will allow President Nicolas Maduro to eliminate democratic checks and balances and install an authoritarian single-party system. (AP Photo/Ariana Cubillos)

The new assembly will be convened within 72 hours of the election and will function with virtually unlimited powers. Maduro and his closest allies have vowed to use the assembly to jail key opposition leaders, remove the nation's outspoken chief prosecutor from her post and strip opposition legislators of their constitutional immunity.

Many in the opposition fear it will mark the end of democracy in Venezuela.

Maduro's mentor, the late President Hugo Chavez, similarly called for a constitution rewrite shortly after taking office in 1999, but unlike Maduro he held a referendum first to get Venezuelans' blessing. Even some "Chavistas" have rejected the drive to change the constitution, which has further polarized an already deeply divided country.

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HOW WILL DELEGATES BE CHOSEN?

Venezuela's government-stacked National Electoral Council created an unorthodox voting system that opponents say heavily favors the ruling party.

A total of 364 delegates will be selected according to geography: In each of Venezuela's 23 states, one delegate will be allotted per municipality while state capitals get two.

But some of the most populated states have relatively few municipalities, while some smaller ones have many. That means a state like Miranda, population nearly 3 million, will get four fewer delegates than Falcon, which is home to about 1 million people.

A supporter of Venezuela's President Nicolas Maduro holds a doll of the late President Hugo Chavez holding a sign that reads in Spanish "Constituent Assembly, Yes it's going" during a political rally with Venezuela's President Nicolas Maduro, in Caracas, Venezuela, Thursday, July 27, 2017. President Maduro has provoked international outcry and enraged an opposition demanding his resignation with his push to elect an assembly that will rewrite the troubled South American nation's constitution. Sunday's election will cap nearly four months of political upheaval that has left thousands detained and injured and at least 100 dead. (AP Photo/Ariana Cubillos)

Critics say that unfairly favors rural areas where Maduro is more popular over opposition-friendly cities such as Caracas, the capital.

An additional 173 delegates will come from various categories of social groups including laborers, students, farmers and fishermen. Eight slots are reserved for indigenous communities. How the government determined who qualifies in each category has not been disclosed, but all of those sectors traditionally have strong ties to Chavez and Maduro's leftist political movement.

The opposition is boycotting the election, so the majority of candidates represent the ruling socialist party.

A poster that shows some of Venezuela's opposition leaders holding a sign with a message that reads in Spanish: "that constituent assembly will not pass" is displayed on a wall near Altamira Square in Caracas, Venezuela, Friday, July 28, 2017. Venezuelan President Nicolas Maduro has provoked international criticism and enraged his political opponents by pushing for a special assembly to rewrite the nation's constitution. Pictured in the poster are Henrique Capriles, left, Lilian Tintori, second left, Maria Corina Machado, second right, and National Assembly President Julio Borges, right. (AP Photo/Ariana Cubillos)

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WHAT CHANGES HAS THE GOVERNMENT VOWED TO MAKE?

Maduro has characterized the constituent assembly as a lofty solution for Venezuela's long list of political and economic woes — and a concrete way of silencing his most vocal foes.

In an address on state-run television Saturday, Maduro said he wants the assembly to strip legislators in the opposition-controlled National Assembly of their immunity and see at least one of them jailed — Freddy Guevara, the legislature's first vice president and one of the highest-profile organizers of protests against the government.

"This little Hitler has his cell guaranteed!" Maduro shouted, using his frequent nickname for Guevara.

On Wednesday, first lady Cilia Flores, who Maduro calls Venezuela's "First Combatant," said the assembly will create a peace and justice commission that will ensure those responsible for the current political upheaval "pay and learn their lesson."

Diosdado Cabello, first vice president of Venezuela's socialist party, has said the office of Venezuela's chief prosecutor, who has recently become one of Maduro's most outspoken critics, will be "turned upside down."

The assembly is certain to continue the socialist policies first installed by Chavez.

Aside from rewriting the constitution, the National Constituent Assembly could function as a sort of super-body that assumes the powers of the National Assembly, the only government branch not controlled by Maduro.

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WHAT DO VENEZUELANS THINK OF THE PLAN?

A June survey by Venezuelan polling firm Datanalisis said just 23 percent favor the constituent assembly. Only 19 percent said they thought a new constitution would "guarantee the peace of stability of the country," as Maduro has asserted. Nearly half said they believe the purpose of the assembly is to ensure Maduro stays in power.

Earlier this month, more than 7.5 million Venezuelans voted in an unofficial opposition referendum rejecting the constitution rewrite.

But those numbers do not mean Venezuelans are unlikely to show up at polling stations Sunday. Aside from government loyalists, groups of state workers and government organization are being mobilized and pressured to cast ballots.

Luis Vicente Leon, president of Datanalsis, said that because the government has access to data showing who does and does not vote, many people are likely to feel obligated to participate or risk losing their jobs in a country with severe food shortages and triple-digit inflation.

"If this was a free election, without pressure, about a third of the number that participated in the popular consult would vote," he said, referring to the opposition referendum.

FILE - In this July 16, 2017 file photo, a marked ballot lays inside an election box during a symbolic referendum in Caracas, Venezuela. Venezuela's opposition called for a massive turnout Sunday in a symbolic rejection of President Nicolas Maduro's plan to rewrite the constitution, a proposal that's escalating tensions in a nation stricken by widespread shortages and more than 100 days of anti-government protests. (AP Photo/Jesus Hernandez, File)

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WHAT IS AT STAKE FOR THE GOVERNMENT?

Its survival.

Recent breaks with Maduro by high-level officials including longtime government loyalist Luisa Ortega Diaz, the chief prosecutor, and a string of former Cabinet ministers under Chavez indicate discord already exists within the ruling party.

Radical changes in the 1999 constitution, which was crafted by Chavez and considered one of his crowning legacies, could cause even greater division, said John Magdaleno, director of the Caracas-based consulting firm POLITY.

"It's not just a matter of whether the constituent assembly is put in place or not," he said. "It's what impact its creation could have."

Foreign governments including the United States have threatened to further isolate the government.

President Donald Trump has said the U.S. will take "strong and swift economic actions" if the constituent assembly election proceeds. That could potentially include reducing U.S. imports of Venezuelan oil, a move that could cripple the economy. The government relies heavily on the U.S. as a source of hard currency, because its oil exports to other major trade partners like China are paying off debts.

A man holds up a poster that reads in Spanish: "Constituent Assembly - Imposed on us, Empty and It perpetuates more poverty" at a barricade set up by demonstrators on the second day of a 48-hour general strike in protest of government plans to rewrite the constitution, in Caracas, Venezuela, Thursday, July 27, 2017. Venezuela is less than three days from a vote that would start the process of rewriting its constitution by electing members of a special assembly to reshape the charter. The opposition is boycotting the vote, saying election rules were rigged to guarantee President Nicolas Maduro a majority in the constitutional assembly. (AP Photo/Ariana Cubillos)

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HOW IS THE OPPOSITION LIKELY TO RESPOND?

The conflict between the government and the opposition won't end Sunday.

A coalition of Venezuelan opposition parties proposed but then appeared to back away from its call to form an alternative "government of national unity." Nonetheless, a recent move by the opposition-controlled National Assembly to appoint 33 magistrates to replace the government-stacked Supreme Court again raised the specter of a potential parallel government.

"The question is whether that parallel government could govern," said Leon, the pollster.

For now, any alternative officials named by the opposition remain purely symbolic. Three of the 33 opposition-appointed magistrates have been detained, while the others have been threatened with arrest and are unable to fill their posts.

A prolonged conflict appears increasingly likely. Third parties have sought unsuccessfully to forge negotiations between the administration and its foes. Guevara told Venezuelans Saturday to prepare for difficult days ahead.

"After Sunday, it will not be easy for us," he said.

The next presidential election is now set for next year, but the constituent assembly could change that and further anger the opposition.

"We're talking about a conflict that will last until there are elections," said Benigno Alarcon, director of the Center of for Political Students at Andres Bello Catholic University in Caracas.

Bolivarian National Guards charge on anti-government demonstrators in Caracas, Venezuela, Friday, July 28, 2017, two days before the vote to begin the rewriting of Venezuela's constitution. Protesters say the election of a constitutional assembly will allow President Nicolas Maduro to eliminate democratic checks and balances and install an authoritarian single-party system. (AP Photo/Ariana Cubillos)