Venezuela’s opposition and President Nicolas Maduro’s government are locked in a high-stakes standoff as each side claims victory in Sunday’s presidential vote.

CARACAS, Venezuela (AP) — As thousands of people demonstrated across Venezuela, opposition candidate Edmundo González announced Monday that his campaign has the proof it needs to show he won the country’s disputed election in which electoral authorities named President Nicolás Maduro the victor.

González and opposition leader Maria Corina Machado told reporters they have obtained more than 70% of tally sheets from Sunday’s election, and they show González with more than double Maduro’s votes. Both called on people, some of whom protested in the hours after Maduro was declared winner, to remain calm and invited them to gather peacefully at 11 a.m. Tuesday to celebrate the results.

“I speak to you with the calmness of the truth,” González said as dozens of supporters cheered outside campaign headquarters in the capital, Caracas. “We have in our hands the tally sheets that demonstrate our categorical and mathematically irreversible victory.”

Their announcement came after the National Electoral Council, which is loyal to Maduro’s ruling Unites Socialist Party of Venezuela, officially declared him the winner, handing him his third six-year term.

Thousands of demonstrators took to the streets of Venezuela on Monday to protest the victory of Nicolás Maduro in the country’s presidential election.

In the capital, the protests were mostly peaceful, but when dozens of riot gear-clad national police officers blocked the caravan, a brawl broke. Police used tear gas to disperse the protesters, some of whom threw stones and other objects at officers who had stationed themselves on a main avenue of an upper-class district.