A candidate from Venezuela's ruling party on Sunday conceded defeat in a tense gubernatorial election in Barinas, a fiefdom of late president Hugo Chavez.
Jorge Arreaza, who served as the country's vice president and foreign minister and was Chavez's son-in-law, tweeted that according to "the information of our structures... we did not succeed".
The National Electoral Council (CNE) was yet to announce the results of the vote.
A first ballot was canceled by a court mid-count last year on the brink of an opposition victory that unnerved the establishment, and thousands of police and soldiers kept a watchful eye on elections Sunday.
The rerun gubernatorial election in Barinas state, where Chavez's father and brothers have held political power since 1998, was conducted amid widespread claims of ruling party interference.
Arreaza, 48, faced off against unknown lawmaker Sergio Garrido, 54, as the ruling party sought to butter up voters with investments in the region, which led many to view the election as stacked in Arreaza's favor.
"We are going to win with the immortal spirit of Comandante Chavez!" President Nicolas Maduro had said on Twitter Sunday.
For his part, Garrido predicted: "We will have the same result of the 21st (of November), but stronger," adding voter turnout was higher.
Sunday's vote came after the regional election on November 21 that appeared to be going the way of opposition figure Freddy Superlano.
That ballot count was stopped by a court as Superlano claimed what would have been the first defeat in Barinas in 23 years for the United Socialist Party of Venezuela (PSUV), now headed by Maduro.
A week later, Venezuela's Supreme Court -- accused of pro-government bias by the opposition and observers -- annulled the preliminary result, which showed Superlano leading.
It granted a request by the country's public finances watchdog to declare Superlano "ineligible" due to "administrative and criminal investigations" into accusations of corruption, and ordered new elections to be held without him.
Superlano is an ally of opposition leader Juan Guaido.
Guaido is recognized by the United States and dozens of other governments as Venezuela's true president over Maduro, whose 2018 re-election was rejected as illegitimate by part of the international community.
With Superlano out of the running and other would-be challengers disbarred, the Popular Will opposition party put forward Garrido for the rerun.
The PSUV and Maduro's government were set on leaving little to chance this time.
Officials delivered social housing in Barinas and unveiled numerous public works projects during the campaign.
Roberto Picon, a member of Venezuela's National Electoral Council (CNE), which is dominated by PSUV backers, is among those to have denounced abuses by officialdom.
The CNE's powers, he said on Twitter, "are insufficient to control a concerted action of the State in the electoral campaign such as demonstrated in Barinas."
Maduro's party won 19 gubernatorial races in the November 21 vote.
Barinas was alone among Venezuela's 23 states not to have the outcome confirmed by the CNE.
EU observers said the vote countrywide was marred by irregularities, including the widespread use of state resources by the PSUV, and "arbitrary disqualifications" of challengers.
"The opposition won and they (the ruling party) didn't like it, because they wish to continue with their hegemony and dynasty," said Nelson Leon, a 68-year-old music teacher who voted near Plaza Bolivar in the state capital, Barinas, on Sunday.
Chavez's father, Hugo de los Reyes Chavez, was governor of Barinas from 1998 to 2008.
He was followed by Hugo Chavez's brother Adan -- a former Venezuelan ambassador to Cuba -- and then older brother Argenis from 2017.
Hugo Chavez remains popular in Barinas -- beloved by many for redistributing the country's vast oil wealth to the poor, but also blamed for the country's now miserable economy and sky-high crime rate.
Venezuela is battered by recession and hyperinflation, and three in four of its citizens live in extreme poverty, according to a recent study.
Millions have left the country in recent years to try their luck elsewhere.
Over 600,000 of Barinas's 870,000 inhabitants were eligible to cast ballots at 543 polling stations; they closed six hours after they opened.
Some 15,000 soldiers and 10,000 other security personnel were deployed to watch voting sites.