(Adds U.S. reaction, details on 2018 election)
CARACAS, Oct 16 (Reuters) - Venezuela's opposition cried foul on Monday over the ruling socialists' surprise win in gubernatorial elections, raising the prospect of more foreign sanctions against the country as France and the United States both criticized the vote.
President Nicolas Maduro's candidates took 17 governorships, versus five for the opposition, in Sunday's nationwide poll, according to the pro-government electoral board.
The socialists' strong showing came despite devastating food shortages, triple-digit inflation, and a collapsing currency. Polls had suggested the opposition would easily win a majority.
Dismayed leaders of the Democratic Unity coalition decried irregularities, called for street action, and demanded an audit, but they did not offer detailed evidence of fraud.
"Neither Venezuelans nor the world will swallow this fiction," said opposition campaign chief Gerardo Blyde.
One losing candidate, Carlos Ocariz who ran for Miranda state, alleged a litany of abuses ranging from multiple voting, state food handouts on the day of the poll, forced attendance at gunpoint, and suspicious phone and power outages.
Opposition leaders also said the election board skewed the poll by moving several hundred vote centers out of their strongholds, and confused people by keeping the names of opposition candidates eliminated in primaries on the ballot.
"The system is totally fraudulent," said Ocariz.
Many dispirited opposition supporters now hope foreign pressure will hurt Maduro.
The United States on Monday condemned the elections as neither free nor fair and vowed to keep up pressure on Maduro.
"As long as the Maduro regime conducts itself as an authoritarian dictatorship, we will work with members of the international community and bring the full weight of American economic and diplomatic power to bear in support of the Venezuelan people as they seek to restore their democracy," State Department spokeswoman Heather Nauert said in a statement.
The Trump administration has already imposed sanctions on Maduro and top officials, including election board head Tibisay Lucena. Washington has also struck at the government's ability to raise more funds via foreign debt.
The European Union could also take measures against Maduro, a former bus driver and foreign minister narrowly elected to replace the late leader Hugo Chavez in 2013. France, whose President Emmanuel Macron has also called Venezuela a dictatorship, expressed concern at claims of "serious irregularities" and "lack of transparency".
2018 PRESIDENTIAL VOTE EYED
Sunday's disputed results will likely dash opposition hopes the unpopular Maduro can be removed in next year's presidential election, and could worsen disagreements over strategy in the perennially divided opposition coalition.
Venezuela's government does retain significant support in poorer, rural settings. And it seems unlikely that supporters of the elite-led opposition, which has struggled to capitalize on discontent over the economy, will return to the streets en masse after months of grueling protests earlier this year.
The actions failed to pressure the government into holding an early presidential election, freeing scores of jailed activists or accepting foreign humanitarian aid.
At least 125 people died, while thousands were injured and arrested in violence.
"Obviously, this was a brutal fraud," said David Osorio, 21, who lost an eye when he was hit by a gas cannister in the clashes. "But I don't know if going back to the streets is best ... because the same will happen and many are simply not willing."
Various opposition leaders acknowledged disillusionment and people staying home had played a big role.
"We shot ourselves in the foot," legislator Jose Guerra said, noting record turnout of 74 percent in a 2015 congress vote, which the opposition won, versus 61 percent on Sunday.
The opposition's electoral setback could further speed a flow of emigrants to other Latin American countries, Spain, and the United States, as many Venezuelans now fear the long-running political crisis will drag on for years.
'WHEN THEY LOSE, THEY CRY FRAUD'
Flanked by his powerful wife, soldiers, and red-shirted party members, a jubilant Maduro painted the opposition as sore losers. "When they lose they cry fraud. When they win they shout 'Down with Maduro,"' said Maduro, 54.
The opposition pocketed governorships including the turbulent Andean states of Merida and Tachira and the oil-producing region of Zulia. The government, which had previously controlled 20 governorships, took states across Venezuela's languid plains and steamy Caribbean coast.
It won back populous Miranda state, which includes part of the capital Caracas, and also won in Barinas, Chavez's home state, where his younger brother retained the top job.
Results for one of the 23 states, southern Bolivar, were still not given by Monday afternoon, though on Sunday the board's website briefly gave it to the opposition.
The opposition has denounced fraud in past votes, but it has lacked substantial detailed evidence and there were no conventional foreign observer missions for Sunday's election.
(Additional reporting by Andrew Cawthorne, Andreina Aponte, Diego Ore, Eyanir Chinea, Corina Pons, Girish Gupta in Caracas, Isaac Urrutia in Maracaibo and Arshad Mohammed in Washington D.C.; Writing by Alexandra Ulmer and Girish Gupta; Editing by Andrew Cawthorne and Tom Brown)