CARACAS, Venezuela (AP) — The number of Venezuelans who participated in the election for an all-powerful constituent assembly was inflated by at least 1 million votes in an official count, the head of a voting technology company asserted Wednesday, a finding certain to sow further discord over the controversial super-body that has generated months of nationwide protests.

Smartmatic CEO Antonio Mugica said results recorded by his systems and those reported by Venezuela’s National Electoral Council indicate “without any doubt” that official turnout figure of more than 8 million participants was manipulated.

The international software company has been providing electronic machines in Venezuela since 2004.

“Even in moments of deep political conflict and division we have been satisfied with the voting process and the count has been completely accurate,” Mugica told reporters in London. “It is, therefore, with the deepest regret that we have to report that the turnout figures on Sunday, 30 July, for the Constituent Assembly in Venezuela were tampered with.”

The assembly will be granted vast powers to rewrite the nation’s constitution and override every branch of the government. Opposition members boycotted the election, claiming the terms to select delegates were heavily rigged to favor the ruling party. President Nicolas Maduro has vowed to use the assembly to target his enemies and solidify Venezuela as a socialist state.

An independent exit poll concluded turnout was less than half that reported by the election commission. Opposition leaders who stationed observers in every municipality also questioned the count.

Julio Borges, the president of the opposition-controlled National Assembly, said lawmakers will ask the nation’s chief prosecutor to investigate commission members for potential crimes.

“They want to give total power to an assembly who people with more than 10 years managing the electoral process in Venezuela say with all certainty, irreversibly, with hard data from their own servers, that the announced result was crooked,” Borges said.

The assembly is expected to be sworn into office Thursday. Opposition leaders are calling on Venezuelans to gather in Caracas for a mass protest.

On Monday, two prominent opposition leaders were dragged from their homes by heavily armed security agents and thrown in a military prison Tuesday, drawing condemnation from the United States and some Latin American countries. But many other nations and international organizations were silent or limited themselves to expressions of concern.

Opposition leader Leopoldo Lopez and Antonio Ledezma were accused by the government-allied Supreme Court of violating the terms of their house arrest by plotting to escape and releasing video statements criticizing Maduro.

Both men’s supporters denied the charges and vowed to continue to try to push the ruling socialist party from power. However, they gave little indication of how they planned to do that, and the capital was unusually quiet after months of sometimes violent protests.

Lopez’s supporters released a video that he taped last week saying he expected to be imprisoned again soon, and calling on Venezuelans to be firm in resisting Maduro.

“If you are looking at this video now, it’s precisely because that occurred, because they came and they illegally imprisoned me again unjustly, a prisoner of consciousness, a prisoner for my ideas, a prisoner for wanting a better Venezuela,” the 46-year-old Lopez said.

He also said that his wife, Lilian Tintori, is pregnant, touching her belly and saying he has “one more reason to fight for Venezuela.” He called the pregnancy “the best news I’ve received in the last 3 1/2 years” — the time he spent behind bars before being released to house arrest last month. The couple had been allowed some conjugal visits.

Maduro appeared undeterred in his plans to seat a special assembly this week with powers to rewrite the constitution and override any other branch of the Venezuelan government. He has threatened to use those powers to go after his opponents and the arrests Tuesday appeared to show he is willing to proceed with full force.

Maduro appeared to have the full support of the country’s most important institutions.

Maduro called the vote for the constitutional assembly in May after weeks of protests fed by anger at his government over food shortages, triple-digit inflation and high crime. Many people accuse the ruling party of corruption and mismanagement.

The Trump administration on Monday added Maduro to a growing list of high-ranking Venezuelan officials targeted by financial sanctions. But the U.S. held off on sanctioning Venezuela’s oil industry, which could undermine Maduro’s government but also deepen the humanitarian crisis in Venezuela.

Maduro scoffed at the sanctions. He has said he would use the assembly’s powers to bar opposition candidates from running in gubernatorial elections in December unless they negotiate an end to protests that have resulted in at least 120 deaths and nearly 2,000 injuries over the past four months.

U.S. Secretary of State Rex Tillerson said Tuesday that the Trump administration was “evaluating all of our policy options as to what can we do to create a change of conditions where either Maduro decides he doesn’t have a future, and wants to leave of his own accord, or we can return the government processes back to their constitution.”

Later, the White House issued a statement condemning “the Maduro dictatorship” over the arrests and saying Lopez and Ledezma are political prisoners.

“The United States holds Maduro — who publicly announced just hours earlier that he would move against his political opposition — personally responsible for the health and safety of Mr. Lopez, Mr. Ledezma, and any others seized,” the White House said.