Turnout figures in Venezuela's Constitutional Assembly election were manipulated by at least one million votes, says Smartmatic, a company that has worked with Venezuela since 2004 on its voting system.

"We know, without any doubt, that the turnout of the recent election for a National Constituent Assembly was manipulated," Antonio Mugica, Venezuelan CEO of Smartmatic, said Wednesday at a news briefing in London.

Mugica said Smartmatic, which has provided electronic voting technology for elections around the world, was able to detect the overstated officially announced turnout because of Venezuela's automated election system.

"We estimate the difference between the actual participation and the one announced by authorities is at least one million votes," he said.

Mugica declined to directly answer whether the manipulated turnout numbers changed the result of the election, in which authorities said 8.1 million people voted.

VENEZUELA-POLITICS/MADURO

Venezuela's President Nicolas Maduro, left, is shown on July 31. Maduro accuses Smartmatic of bending to U.S. pressures aimed at casting doubt on the official results. (Miraflores Places via Reuters)

Smartmatic began providing electronic voting machines in 2004 during the presidency of the late Hugo Chavez.

The president of Venezuela's electoral council called Mugica's statement "irresponsible." Tibisay Lucena also said legal action could be taken against Smartmatic.

The election of the legislative super body has been decried by critics as illegitimate and designed to give the unpopular government of President Nicolas Maduro powers to rewrite the Constitution and sideline the opposition-led congress.

Mugica said the authorities in Venezuela would likely not be sympathetic to his comments and that he had not yet passed the evidence to the Venezuela's electoral council.

On Wednesday night, Maduro accused Smartmatic of bending to U.S. pressures aimed at casting doubt on the official results.

According to internal electoral council data previously reviewed by Reuters, only 3.7 million people had voted by 5:30 p.m. in the election Sunday.

Venezuelan authorities have not responded for comment on their official tally and the apparent discrepancies.

The swearing-in of delegates to the 545-member assembly began Wednesday, with its first session scheduled for Friday.

With files from The Associated Press