CARACAS, Venezuela — Venezuela’s opposition presented evidence Thursday of possible ballot tampering in gubernatorial elections, seeking to bolster its claim that its shock loss at the polls was the result of fraud.

The Democratic Unity Roundtable’s claim rests on results from a single race, in industrial Bolivar state, where pro-government candidate Justo Noguera was declared the winner by just 1,471 votes over opposition candidate Andres Velasquez.

The opposition coalition said the results on the National Electoral Council’s website don’t match the tallies from 11 ballot boxes certified by poll workers representing multiple political parties. It said the inconsistencies resulted in 2,199 votes from those polling stations being awarded incorrectly to Noguera, enough to swing the vote in his favor.

Electoral authorities had no immediate comment.

For the opposition, the disputed figures represent a glimmer of hope following days of internal feuding in which crestfallen leaders have alternately blamed their big loss in Sunday’s regional elections on voter apathy, strategic missteps and a series of pre-election maneuvers by the government to suppress turnout.

Pre-election polls predicted that popular outrage over triple-digit inflation, widespread food shortages and the recent crackdown on dissent gave the opposition a virtual lock on the majority of Venezuela’s 23 governorships. But in the end, President Nicolas Maduro’s opponents carried only five districts, suffering defeat even in strongholds such as Miranda state surrounding Caracas that was engulfed by months of anti-government unrest earlier this year.

The contest in Bolivar state was the only one not called on election night because results were too tight. Although far from the political battles of Caracas, the state is a vital economic motor that is home to a major steel factory. It’s also where the government is working with private companies to expand large-scale mining in a bid to diversify the economy away from oil exports and generate badly needed hard currency.

Noguera, the former head of Venezuela’s national guard, was slapped with sanctions by the U.S. in 2015 for human rights violations committed by security forces during a crackdown on protesters in 2014.

Venezuela’s electronic voting system is technically robust and considered tamper-proof when manual audits of printed tallies from voting machines are performed, as they were Sunday. Indeed, most of the opposition’s claims of “fraud” have until now been based on claims of alleged voter intimidation before election day and not tinkering with actual tallies.

“But in Bolivar they’ve crossed that final threshold of just straight up stealing an election,” said Francisco Toro, editor of Caracas Chronicles, a popular opposition blog. “It changes the dynamics of the political game from now on.”

The government is showing no sign of backing down.

On Thursday, Maduro warned that opposition gubernatorial winners who don’t swear loyalty to a pro-government constitutional assembly will not be allowed to take office and added that they could be removed and even jailed if they use their new posts to plot against him.

“They either show respect, or they show respect, it’s that simple,” Maduro said at an event to celebrate the government’s victory in Miranda.

All five opposition governors have so far refused to take the loyalty oath to the constitutional assembly, which they and many foreign governments consider an illegal power grab by Maduro. Venezuelan law requires they take the oath before state legislatures, most of which are dominated by the ruling socialist party and which on Thursday were ordered by the constitutional assembly not to swear in any politician who doesn’t fall into line.

The U.S State Department on Thursday called the requirement “alarming,” saying it was “another example of the Maduro regime’s authoritarianism and disregard for the will of the Venezuelan people.”

The U.S. called for a complete audit of the election by internationally recognized entities and the establishment of an independent national electoral council.