Updated 2:25 a.m. ET
CARACAS, Venezuela Hugo Chavez's hand-picked successor, Nicolas Maduro, won a razor-thin victory in Sunday's special presidential election, edging the opposition's leader by only about 300,000 votes, electoral officials announced.
His challenger, Henrique Capriles, declared that he wouldn't accept the results and called for a full recount.
Maduro's stunningly close victory came after a campaign in which the winner promised to carry on Chavez's self-proclaimed socialist revolution while Capriles' main message was that Chavez's 14-year regime put Venezuela on the road to ruin.
Maduro, acting president since Chavez's death, held a double-digit advantage in opinion polls just two weeks ago, but electoral officials said he got just 50.7 percent of the votes to 49.1 percent for Capriles with nearly all ballots counted.
Chavistas set off fireworks and blasted car horns as they cruised downtown Caracas in jubilation.
In a victory speech, Maduro told a crowd outside the presidential palace that his victory was further proof that Chavez "continues to be invincible, that he continues to win battles."
At Capriles' campaign headquarters, people hung their heads quietly as the results were announced by an electoral council stacked with government loyalists. Many started crying; others just stared at TV screens in disbelief.
But Capriles emerged later to angrily reject the official vote totals.
"It is the government that has been defeated," he said.
Capriles said at his campaign's headquarters that his campaign's tally of votes came up with "a result that is different from the results announced today."
"The biggest loser today is you," he said, directly addressing Maduro through the camera. "The people don't love you."
Maduro said during his speech that Capriles had called him before the results were announced to suggest a "pact" and that Maduro refused.
There was no comment from Capriles' camp on Maduro's claim.
Maduro, a longtime foreign minister to Chavez, rode a wave of sympathy for the charismatic leader to victory, pinning his hopes on the immense loyalty for his boss among millions of poor beneficiaries of government largesse and the powerful state apparatus that Chavez skillfully consolidated.
Capriles' main campaign weapon was to simply emphasize "the incompetence of the state" in handling the world's largest oil reserves.
Millions of Venezuelans were lifted out of poverty under Chavez, but many also believe his government not only squandered, but plundered, much of the $1 trillion in oil revenues during his tenure.
Venezuelans are afflicted by chronic power outages, crumbling infrastructure, unfinished public works projects, double-digit inflation, food and medicine shortages, and rampant crime -- one of the world's highest homicide and kidnapping rates -- that the opposition said worsened after Chavez succumbed March 5 to cancer.
Analyst David Smilde at the Washington Office on Latin America think tank predicted the victory would prove pyrrhic and make Maduro extremely vulnerable.
"It will make people in his coalition think that perhaps he is not the one to lead the revolution forward," Smilde said.
In a hint of discontent within Chavista ranks, National Assembly President Diosdado Cabello, who many consider Maduro's main rival, expressed dismay at the tight outcome.
He tweeted, "The results oblige us to make a profound self-criticism. It's contradictory that the poor sectors of the population vote for their longtime exploiters."
"This is a result in which the 'official winner' appears as the biggest loser," said Amherst College political scientist Javier Corrales. "The 'official loser' -- the opposition -- emerges even stronger than it did six months ago. These are very delicate situations in any political system, especially when there is so much mistrust of institutions."
Turnout was 78 percent, down from just over 80 percent in the October election that Chavez won by a nearly 11-point margin.
Many across the nation put little stock in Maduro's claims that sabotage by the far right was to blame for worsening power outages and food shortages in the weeks before the vote.
"We can't continue to believe in messiahs," said Jose Romero, a 48-year-old industrial engineer who voted for Capriles in the central city of Valencia. "This country has learned a lot and today we know that one person can't fix everything."
In the Chavista stronghold of Petare outside Caracas, Maria Velasquez, 48, who works in a government soup kitchen that feeds 200 people, said she was voting for Chavez's man "because that is what my comandante ordered."
Reynaldo Ramos, a 60-year-old construction worker, said he "voted for Chavez" before correcting himself and saying he chose Maduro. But he could not seem to get his beloved leader out of his mind.
"We must always vote for Chavez because he always does what's best for the people and we're going to continue on this path," Ramos said. He said the government had helped him get work on the subway system and helps pay his grandchildren's school costs.
The governing United Socialist Party of Venezuela deployed a well-worn get-out-the-vote machine spearheaded by loyal state employees. It also enjoyed the backing of state media as part of its near-monopoly on institutional power.
Capriles' camp said Chavista loyalists in the judiciary put them at glaring disadvantage by slapping the campaign and broadcast media with fines and prosecutions that they called unwarranted. Only one opposition TV station remains and it was being sold to a new owner Monday.
At his campaign rallies, Capriles would read out a list of unfinished road, bridge and rail projects. Then he asked people what goods were scarce on store shelves.
Capriles, 40, showed Maduro none of the respect he earlier accorded Chavez. Maduro hit back hard, at one point calling Capriles' backers "heirs of Hitler." It was an odd accusation considering that Capriles is the grandson of Holocaust survivors from Poland.
The opposition contended Chavez looted the treasury last year to buy his re-election with government handouts. It also complained about the steady flow of cut-rate oil to Cuba, which Capriles said would end if he won.
Venezuela's $30 billion fiscal deficit is equal to about 10 percent of the country's gross domestic product.
Maduro, a former union activist and bus driver with close ties to Cuba's leaders, constantly alleged that Capriles was conspiring with U.S. putschists to destabilize Venezuela and even suggested Washington had infected Chavez with the cancer that killed him.
In his victory speech, he said he would be presenting on Monday nine men arrested in an alleged sabotage plot
He focused his campaign message on his mentor, "I am Chavez. We are all Chavez." And he promised to expand anti-poverty programs.
Maduro will face no end of hard choices.
Many factories operate at half capacity because strict currency controls make it hard for them to pay for imported parts and materials. Business leaders say some companies verge on bankruptcy because they cannot extend lines of credit with foreign suppliers.
Chavez imposed currency controls a decade ago trying to stem capital flight as his government expropriated large land parcels and dozens of businesses. Now, dollars sell on the black market at three times the official exchange rate and Maduro has had to devalue Venezuela's currency, the bolivar, twice this year.
Meanwhile, consumers grumble that stores are short of milk, butter, corn flour and other staples. The government blames hoarding, while the opposition points at the price controls imposed by Chavez in an attempt to bring down double-digit inflation.