Venezuela’s prosecutor’s office has asked a court to suspend Friday’s inauguration of a constituent assembly over claims of electoral fraud.
It came after chief prosecutor Luisa Ortega opened an investigation into the allegations, which have been dismissed by President Nicolás Maduro.
A firm that supplied the voting system said turnout figures had been inflated.
The opposition boycotted Sunday’s vote and will hold rallies in the capital, Caracas, as the ceremony takes place.
In a post on Twitter, Ms Ortega’s office said the case had been filed by two state prosecutors “based on suspected crimes committed” during the election.
Ms Ortega was once a close ally of President Maduro but is now one of his fiercest critics.
Luisa Ortega has called for an independent audit of the vote after allegations that the figure for the turnout was inflated.
Her trajectory from party loyalist to thorn in the side of the government has made her future very uncertain.
A close ally of Mr Maduro, Jorge Rodríguez, said it was only a matter of time before she was removed from her post.
“She is the past,” the influential politician said.
The new assembly will have the power to rewrite the constitution and override decisions by the opposition-controlled congress.
Its members were elected in a controversial vote held amid widespread protests and the assembly has been widely condemned abroad.
Smartmatic, the company that supplied the electronic voting system, said that the turnout figures had been inflated by at least one million.
Earlier on Thursday, Ms Ortega said she had appointed two prosecutors to investigate four out of the five directors of the National Electoral Council (CNE) “for this very scandalous act that could generate more violence in the country than what we have already experienced”.
Critics of the council say it is filled with government loyalists who do the president’s bidding.
However, it is unclear how far the investigation will proceed.
Ms Ortega has made previous attempts to challenge executive decisions but they have been blocked.
President Maduro insists the new assembly is needed to restore order to the country after months of political and economic crisis.
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