(CNN) -- Denouncing election irregularities, Venezuelan opposition candidate Henrique Capriles Radonski demanded a recount and said early Monday that he will not recognize the country's presidential results "until every vote is counted." His comments came less than an hour after officials said the man former Venezuelan President Hugo Chavez handpicked to be his successor had won the country's presidential vote. With 99% of votes counted, Nicolas Maduro won 50.66% of votes, National Electoral Council President Tibisay Lucena said, calling the results "irreversible." Capriles won 49.07% of votes, she said. Fireworks erupted over Caracas as Maduro spoke to cheering supporters, calling on Venezuelans to respect the results and respond peacefully.
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NEW: Capriles demands a recount
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Election officials say Maduro won the vote
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Twitter accounts for Maduro and his party are hacked
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Official: 43 people were detained for alleged electoral crimes
@placeholder, who ruled Venezuela for 14 years, celebrated a triumphant re-election victory in October.