Caracas, Venezuela. Venezuela’s opposition claimed victory in Sunday’s presidential election, setting up a showdown with the government, which earlier declared President Nicolás Maduro the winner.

“The Venezuelans and the entire world know what happened,” opposition candidate Edmundo González said in his first remarks.

Opposition leader Maria Corina Machado said the margin of González's victory was “overwhelming" based on voting tallies it had received from campaign representatives from about 40 percent of ballot boxes nationwide.

The National Electoral Council, which is controlled by Maduro loyalists, earlier said Maduro had secured 51 percent of the vote to 44 percent for González. But it didn't release the tallies from each of the 30,000 polling booths nationwide, promising only to do so in the “coming hours,” hampering the ability to verify the results.

Foreign leaders held off recognizing the results.

“The Maduro regime should understand that the results it published are difficult to believe," said Gabriel Boric, the leftist leader of Chile. “We won't recognize any result that is not verifiable.”

US Secretary of State Antony Blinken, speaking in Tokyo, said the US has "serious concerns that the result announced does not reflect the will or the votes of the Venezuelan people.”

The delay in announcing results -- six hours after polls were supposed to close -- indicated a deep debate inside the government about how to proceed after Maduro’s opponents came out early in the evening all but claiming victory.

When Maduro finally came out to celebrate the results, he accused unidentified foreign enemies of trying to hack the voting system.

“This is not the first time that they have tried to violate the peace of the republic,” he said to a few hundred supporters at the presidential palace. He provided no evidence to back the claim but promised “justice” for those who try to stir violence in Venezuela.

Opposition representatives said tallies they collected from campaign representatives at the polling stations showed González trouncing Maduro. Meanwhile, the head of the electoral council said it would release the official voting acts in the coming hours.

Maduro, in seeking a third term, faced his toughest challenge yet from the unlikeliest of opponents in González: a retired diplomat who was unknown to voters before being tapped in April as a last-minute stand-in for opposition powerhouse Maria Corina Machado.

Earlier, opposition leaders celebrated, online and outside a few voting centers, what they assured was a landslide victory for González.

“I'm so happy,” said Merling Fernández, a 31-year-old bank employee, as a representative for the opposition campaign walked out of one voting center in a working-class neighborhood of Caracas to announce results showing González more than doubled Maduro's vote count. Dozens standing nearby erupted in an impromptu rendition of the national anthem.

“This is the path toward a new Venezuela,” added Fernández, holding back tears. "We are all tired of this yoke.”

Voters started lining up at some voting centers across the country before dawn Sunday, sharing water, coffee and snacks for several hours.

The election will have ripple effects throughout the Americas, with government opponents and supporters alike signaling their interest in joining the exodus of 7.7 million Venezuelans who have already left their homes for opportunities abroad should Maduro win another six-year term.

Authorities set Sunday's election to coincide with what would have been the 70th birthday of former President Hugo Chávez, the revered leftist firebrand who died of cancer in 2013, leaving his Bolivarian revolution in the hands of Maduro. But Maduro and his United Socialist Party of Venezuela are more unpopular than ever among many voters who blame his policies for crushing wages, spurring hunger, crippling the oil industry and separating families due to migration.

The opposition managed to line up behind a single candidate after years of intraparty divisions and election boycotts that torpedoed their ambitions to topple the ruling party.

Machado was blocked by the Maduro-controlled supreme court from running for any office for 15 years. A former lawmaker, she swept the opposition's October primary with over 90 percent of the vote. After she was blocked from joining the presidential race, she chose a college professor as her substitute on the ballot, but the National Electoral Council also barred her from registering. That's when González, a political newcomer, was chosen.

Sunday's ballot also featured eight other candidates challenging Maduro, but only González threatens Maduro's rule.

After voting, Maduro said he would recognize the election result and urged all other candidates to publicly declare that they would do the same.

“No one is going to create chaos in Venezuela,” Maduro said. “I recognize and will recognize the electoral referee, the official announcements and I will make sure they are recognized.”

Venezuela sits atop the world's largest proven oil reserves and once boasted Latin America's most advanced economy. But it entered into a free fall after Maduro took the helm. Plummeting oil prices, widespread shortages and hyperinflation that soared past 130,000 percent led first to social unrest and then mass emigration.

Economic sanctions from the US seeking to force Maduro from power after his 2018 reelection -- which the US and dozens of other countries condemned as illegitimate -- only deepened the crisis.