Voting technology firm Smartmatic, which provides the South American OPEC member country's voting machines, said on Wednesday the official turnout figure of 8.1 million votes in Sunday's election had been inflated by at least 1 million votes. The firm did not explain how it reached that conclusion.

"The preliminary investigation points toward the alleged commission of crimes by functionaries of the National Elections Council (CNE), and other people linked to the council," the prosecutor's office said in a statement. It cited Smartmatic's accusation, which President Nicolas Maduro and his government's elections council have denied.

The opposition boycotted the vote, which was condemned by countries around the world as an affront to democracy. The count was crucial for socialist Maduro to legitimize the new, Socialist Party-dominated "constituent assembly," set for inauguration on Friday.

Opposition leaders have called for a march to the center of Caracas on Friday to protest creation of the assembly, which will be empowered to write a new constitution and may dissolve state institutions, including the opposition-led congress.