Venezuelan state prosecutors have said they have asked a court to block the inauguration of a widely criticised new assembly that is set to replace the opposition-majority congress, alleging electoral fraud.
Attorney General Luisa Ortega's office said on Twitter the case was filed by two of its prosecutors, "based on suspected crimes committed" during Sunday's election to choose the powerful Constituent Assembly - a vote boycotted by the opposition and widely condemned abroad.
Ms Ortega has emerged as one of the most vocal critics of President Nicolas Maduro.
Earlier Venezuela's opposition postponed a protest against the new assembly until the body opens tomorrow, amid blistering criticism and a fraud investigation.
The Democratic Unity Roundtable made an announcement on Twitter that the protest would be pushed back to coincide with the planned opening of the controversial Constituent Assembly, which Mr Maduro earlier announced would be delayed.
The dissident group said tomorrow's protest was being held "to defend the constitution."
Mr Maduro has denied that the vote to establish the powerful new assembly was rigged, calling the accusation a "reaction by the international enemy".
He faces mounting accusations of trampling on democracy with Sunday's controversial election for the Constituent Assembly.
British technology firm Smartmatic, which was contracted to handle the vote, said the official figures from the election were "tampered with" to make turnout appear greater than it was.
Mr Maduro rejected the charge: "Nothing can stain this process, because it's transparent," he said at a ceremony for allies elected to the new assembly, vowing electoral authorities would carry out a "100% audit".
The electoral authority itself, which has been criticised as a Maduro mouthpiece, denied the vote-tampering allegation as "an irresponsible contention based on estimates with no grounding in the data".
The new body, whose members include Mr Maduro's wife and son, will have sweeping powers to dissolve the opposition-majority congress, pass laws and write a new constitution.
Despite months of violent protests and international condemnation, Mr Maduro insists it is the solution to a drawn-out economic and political crisis gripping Venezuela.
Mr Maduro said the reason for the delayed launch was that 35 newly-elected members had not yet been officially declared by electoral authorities.
Venezuela has been rocked by four months of clashes at anti-Maduro protests that have left more than 125 people dead.
Sunday's vote brought the crisis to a boiling point, drawing international condemnation.
The United States imposed direct sanctions on Mr Maduro, calling him a "dictator".
The European Union joined the US, Mexico, Colombia and Argentina in saying it would not recognise the new assembly.
