Late socialist leader Hugo Chavez's chosen successor Nicolas Maduro won Venezuela's presidential election by a whisker but now faces opposition protests plus a host of economic and political challenges in the OPEC nation.
The 50-year-old former bus driver, whom Chavez named as his preferred heir before dying from cancer, edged out opposition challenger Henrique Capriles with 50.7 percent of the votes in Sunday's election, according to election board returns. Capriles took 49.1 percent, a difference of just 235,000 ballots.
Capriles, whose strong showing beat most forecasts, refused to recognize the result and said his team had a list of more than 3,000 irregularities ranging from gunshots to the illegal reopening of polling centers.
"I didn't fight against a candidate today, but against the whole abuse of power," said Capriles, the 40-year-old governor of Miranda state, demanding a recount.
"Mr. Maduro, you were the loser ... This system is collapsing, it's like a castle of sand - touch it and it falls."
A protracted election dispute could cause instability in a deeply polarized nation with the world's largest oil reserves.
Though some opposition supporters chanted "fraud," banged pots and pans and burned tires in protest, Capriles did not call them onto the streets en masse.
Maduro said he would accept a full recount, even as he insisted his victory was clean and dedicated it to Chavez.
"We've had a fair, legal and constitutional triumph," Maduro told his victory rally. "To those who didn't vote for us, I call for unity. We are going to work together for the security and economy of this country."
The election board said Maduro's win was "irreversible" and gave no indication of when it might carry out an audit.
Maduro's slim victory provides an inauspicious start for the "Chavismo" movement's transition to a post-Chavez era, and raises the possibility that he could face challenges from rivals within the disparate leftist coalition.
Chavez beat Capriles by 11 percentage points in October, showing how quickly the gap between the two sides has eroded without the larger-than-life presence of the former leader. It raises doubts about the long-term appeal and durability of a movement that Chavez built, led and held together throughout his 14 years in power.
Maduro's supporters set off fireworks and some sang and danced in the streets, but celebrations were far more muted than after Chavez's re-election last year.
Some supporters seemed to pay little attention to Maduro's speech, and it was only when he played a recording of the late president singing the national anthem that they burst into life.
'CHAVISMO' CHALLENGED
"On one hand, we're happy, but the result is not exactly what we had expected," said Gregory Belfort, 32, a computer technician looking slightly dazed with other government supporters in front of the presidential palace.
"It means there are a lot of people out there who support Chavez but didn't vote for Maduro, which is valid."
Russian President Vladimir Putin congratulated Maduro and said he expected good relations to continue with a country where Moscow has big oil investments. Another ally, Argentina's leader Cristina Fernandez, also sent congratulations.
Maduro's narrow win came as a shock to many ardent Chavez loyalists, who had become accustomed to his double-digit election victories.
Maduro's campaign was built almost entirely on his close ties to the late leader and emotional anecdotes about Chavez's final days before he succumbed to cancer last month.
The narrow win leaves Maduro with less authority to lead the broad ruling alliance that includes military officers, oil executives and armed slum leaders. It had been held together mainly by Chavez's iron grip and mesmerizing personality.
"This is the most delicate moment in the history of 'Chavismo' since 2002," said Javier Corrales, a U.S. political scientist and Venezuela expert at Amherst College in Massachusetts, referring to a brief coup against Chavez 11 years ago.
"With these results, the opposition might not concede easily, and Maduro will have a hard time demonstrating to the top leadership of Chavismo that he is a formidable leader."
It will also add to the difficulty Maduro faces in moving from campaign mode to actually governing a nation with high inflation, a slowing economy, Byzantine currency controls and one of the world's worst violent crime rates.
In 2012, blow-out state spending before Chavez's re-election helped spur economic growth of 5.6 percent. This year, many private economists expect growth of 2 percent or less.
In a research note, Barclays said the high uncertainty about the short-term political situation was likely to be received negatively by the market. There were few signs, however, that the situation could force Venezuela to default on its debt.
Venezuela's popular, high-yielding flagship dollar bonds fell sharply on Monday and debt insurance costs rose.
The evaporation of Maduro's big lead in the opinion polls from just last month did prompt some high level soul-searching.
"These results require deep self-criticism," said Diosdado Cabello, the powerful head of the National Assembly whom many Venezuelans see as a potential rival to Maduro.
"It's contradictory that some among the poor vote for those who always exploit them," Cabello added on Twitter. "Let's turn over every stone to find our faults, but we cannot put the fatherland or the legacy of our commander (Chavez) in danger."