Caracas - Venezuela's opposition anticipated victory Sunday after polls closed in a legislative election that leaders have warned risks sparking violence in the oil-rich but impoverished nation.
Electoral authorities had yet to publish any results, but senior figures in the broad opposition coalition MUD started effectively claiming victory.
They included Henrique Capriles and Lilian Tintori, wife of the jailed opposition leader Leopoldo Lopez.
"The results are what we hoped for! Venezuela has won!" Capriles, leader of the Justice First party, wrote on Twitter.
Tintori, whose husband leads the Popular Will party, said in a video message published online: "We have won by a lot, we have won well!"
They did not state where they got their information about the results.
The state National Electoral Council (CNE) had yet to release results and there was no official comment from President Nicolas Maduro's government, though his supporters also celebrated in the street in eastern Caracas.
Squabbling broke out in the evening, with the opposition accusing the government of foul play by keeping polling stations open longer than scheduled.
The opposition is vying to win control of the legislature from the socialist government for the first time in 16 years.
Long lines stretched outside polling stations as voters fed up with soaring prices and food shortages cast their ballots to back the opposition, while others vowed to push on with the "revolution" of the left, in control since 1999.
Opponents have accused Maduro of rigging voting districts and intimidating them. Numerous opposition figures are in jail.
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US and European authorities have condemned the jailing of Lopez and called for a free and open election.- Disillusioned socialists -
Surveys by Venezuelan pollsters such as Datanalisis have shown the opposition is likely to win a majority in the legislative National Assembly for the first time since late socialist leader Hugo Chavez was first elected in 1999.
But analysts say they may struggle to counter Maduro's presidential powers.
The country of 30 million is in an economic crisis due to plunging oil revenues, with families suffering shortages of basic foods and supplies.
Queuing to cast his ballot at a school in central Caracas, 24-year-old fast-food worker Filros Guzman said he used to vote for the government, but was now fed up with being unable to find toilet paper and enough food in the shops.
"I liked the socialist ideology of an equal society. But now I have changed my mind because of everyday problems," he told AFP.
"You can't vote for the government when you're having difficulty surviving."
Others want the ruling PSUV party to keep control of congress so it will continue approving the social spending programs of Maduro and his late predecessor, "Comandante" Chavez, father of the "Bolivarian revolution."
"There is no turning back. Revolution and nothing else," said mechanic Gilberto Marcano, 73, as he stood in line to vote in northern Caracas. "I will never do wrong to my comandante."- Fears of violence -
Since the mustachioed former bus driver Maduro was elected after Chavez's death in 2013, soaring inflation has slashed families' spending power.
Maduro promised to respect the results as he voted in western Caracas, dressed in his party's red jacket.
"A key task for the new National Assembly will be to bring about economic recovery, to attack hoarders, speculators, and those who are hiding products," he said.
Maduro regularly alleges US-backed businesses are waging an "economic war" against Venezuela.
Some analysts say Venezuela risks political deadlock and leaders including Capriles have warned of a repeat of anti-government riots that left 43 people dead last year.
"The big problems are the lack of security and the high cost of living," said William Carrasco, 55. "Things could get violent."