(Adds Chinese comment; paragraphs 22,23)
By Luc Cohen and Vivian Sequera
CARACAS, May 21 (Reuters) - Venezuela's socialist leader Nicolas Maduro faced fresh international censure on Monday after re-election in a vote foes denounced as a farce cementing autocracy in the crisis-stricken OPEC nation.
The 55-year-old successor to former president Hugo Chavez hailed his win as a victory against "imperialism," but his main rival refused to recognize the result alleging irregularities.
Thousands of Maduro supporters, many wearing red berets, hugged and danced outside the Miraflores presidential palace as the results came in, under confetti in the yellow, blue and red colors of the Venezuelan national flag.
"The revolution is here to stay!" a jubilant Maduro told the crowd, promising to prioritize economic recovery after five years of recession in the nation of 30 million people.
"Let's go, Nico!" his supporters chanted until after midnight during party scenes in downtown Caracas.
"We mustn't cave to any empire, or go running to the International Monetary Fund as Argentina did. The opposition must leave us alone to govern," said government supporter Ingrid Sequera, 51, wearing a T-shirt with a logo of Chavez's eyes.
Declaring Sunday's vote a "sham," the United States is now threatening sanctions on Venezuela's all-important oil sector, which is already reeling from falling output, a brain-drain and creaking infrastructure.
The European Union and major Latin Americans repeatedly warned in advance that conditions were unfair.
Chile's President Sebastian Pinera was scathing about Sunday's vote. "Venezuela's elections do not meet minimum standards of true democracy," he said. "Like most major democratic nations, Chile does not recognize these elections."
Panama's government followed suit, quickly saying it would not recognize the result. But fellow leftist-run nations Cuba and El Salvador sent congratulations.
Venezuela's mainstream opposition boycotted the vote, given that two of its most popular leaders were barred, authorities had banned the coalition and various of its parties from using their names, and the election board is run by Maduro loyalists.
The government used ample state resources during the campaign and pressure was put on state workers to vote.
The election board said Maduro took 5.8 million votes, versus 1.8 million for his chief challenger Henri Falcon, a former governor who broke with the boycott to stand.
Turnout at the election was 46 percent, it said, way down from the 80 percent at the last presidential vote in 2013.
Falcon called for a new vote, complaining about the government's placing of nearly 13,000 pro-government stands called "red spots" close to polling stations nationwide.
Mainly poor Venezuelans were asked to scan state-issued "fatherland cards" at red tents after voting in hope of receiving a "prize" promised by Maduro.
The "fatherland cards" are required to receive benefits including food boxes and money transfers.
Maduro now faces a colossal task to turn around Venezuela's moribund economy and offered no specifics on reforming two decades of state-led policies. The bolivar currency is down 99 percent over the past year and inflation is at an annual 14,000 percent, according to the National Assembly.
Furthermore, Venezuela's multiple creditors are considering accelerating claims on unpaid foreign debt, while oil major ConocoPhillips has been taking aggressive action to seize state oil company PDVSA's assets over a 2007 nationalization.
Though increasingly shunned in the West, Maduro can at least count on the support of major powers China and Russia, who have provided billions of dollars' funding in recent years.
In Beijing, foreign ministry spokesman Lu Kang said China believed the Venezuelan government and people could handle their own affairs and that everyone should respect the choice of the Venezuelan people.
Asked if China had sent congratulations to Maduro, he said China would "handle this in accordance with diplomatic convention", but did not elaborate.
U.S. Republican senator Marco Rubio, a strident critic of Maduro, urged isolation of his government and said he supported "all policy options" to return Venezuela to democracy.
U.S. President Donald Trump has said in the past he would not rule out military action against Venezuela. (Additional reporting by Maria Ramirez in Ciudad Guayana; Alexandra Ulmer in Caracas, and Ben Blanchard in BEIJING Writing by Angus Berwick Editing by Andrew Cawthorne)
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