Hugo Chavez's hand-picked successor, Nicolas Maduro, has officially won Venezuela's presidential election by a stunningly narrow margin that highlights rising discontent over problems ranging from crime to power blackouts. His rival demanded a recount, portending more headaches for a country shaken by the death of its dominating leader.

One key Chavista leader expressed dismay over the outcome of Sunday's election, which was supposed to cement the self-styled "Bolivarian Revolution" of their beloved president as Venezuela's destiny. National Assembly President Diosdado Cabello, who many consider Maduro's main rival within their movement, tweeted: "The results oblige us to make a profound self-criticism."

Maduro's victory followed an often ugly, mudslinging campaign in which the winner promised to carry on Chavez's legacy, while challenger Henrique Capriles' main message was that Chavez put this country with the world's largest oil reserves on the road to ruin.

Despite the ill feelings, both men sent their supporters home and urged them to refrain from violence. Capriles insisted on a recount and Maduro said he was open to one, though it was not immediately clear if election officials might permit it.

"We are not going to recognize a result until each vote of Venezuelans is counted," Capriles said. "This struggle has not ended."

Maduro, meanwhile, said, "Let 100 percent of the ballot boxes be opened. ... We're going to do it; we have no fear."

Maduro, acting president since Chavez's March 5 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 compared to 49.1 percent for Capriles, with nearly all ballots counted.

The margin was about 234,935 votes out of 14.8 million cast. Turnout was 78 percent, down from just over 80 percent in the October election that Chavez won by a nearly 11-point margin over Capriles.

Chavistas set off fireworks and raced through downtown Caracas blasting horns 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."

But analysts called the slim margin a disaster for Maduro, a former union leader and bus driver in the radical wing of Chavismo who is believed to have close ties to Cuba.

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.

Later, Capriles emerged to angrily reject the official totals: "It is the government that has been defeated."

He said his campaign reported "a result that is different from the results announced today."

"The biggest loser today is you," Capriles said, directly addressing Maduro through the camera. "The people don't love you."

Venezuela's electronic voting system is completely digital, but also generates a paper receipt for each vote, making a vote-by-vote recount possible.

Capriles, an athletic 40-year-old state governor, had mocked and belittled Maduro as a poor, bland imitation of Chavez.

Maduro said during his victory speech that Capriles had called him before the results were announced to suggest a "pact" and that Maduro refused. Capriles' camp did not comment on Maduro's claim, though Capriles began his speech by declaring he doesn't "make pacts with lies or corruption."

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." At 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.

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 14-year rule.

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 disappeared to Cuba in December for what would be his final surgery.

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.

"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."

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 a Chavista stronghold in Petare outside Caracas, Maria Velasquez, 48, who works in a government soup kitchen that feeds 200 people, said she voted 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.

"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.

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 also complained that 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.

Maduro will face no end of hard choices for which Corrales, of Amherst, said he has shown no skills for tackling.

Maduro has "a penchant for blaming everything on his `adversaries' -- capitalism, imperialism, the bourgeoisie, the oligarchs -- so it is hard to figure how exactly he would address any policy challenge other than taking a tough line against his adversaries."

Venezuela's $30 billion fiscal deficit is equal to about 10 percent of the country's gross domestic product.

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.