Venezuelan opposition leader Maria Corina Machado and her coalition's candidate Edmundo Gonzalez have commanded enthusiastic crowds during their campaign to unseat President Nicolas Maduro and end 25 years of ruling party dominance.
But uncertainty remains about how Sunday's election will play out, with Maduro – whose 2018 reelection is considered fraudulent by the United States, among others - sounding a confident note and opposition figures and analysts warning of possible underhandedness.
Gonzalez has attracted significant support, even from former supporters of the ruling party, but the opposition and some observers have questioned whether the vote will be fair, saying decisions by electoral authorities and the arrests of some opposition campaign staff are meant to create obstacles.
Gonzalez and Machado have urged voters to cast ballots early and hold "vigils" at polling stations until they close. They have said they expect the military to uphold the results of the vote.
Venezuela's military has long supported Maduro and his predecessor, the late Hugo Chavez. Defense Minister General Vladimir Padrino has said the armed forces will respect the outcome of Sunday's election.
Maduro, who has been in power since 2013 and is seeking his third six-year term, has said the country has the world's most transparent electoral system and has warned of a "bloodbath" if he were to lose.
Maduro's government has presided over an economic collapse, the migration of about a third of the population and sharply-deteriorated diplomatic relations, crowned by sanctions imposed by the United States, European Union and others which have crippled an already-struggling oil industry.
"We want political and economic change so there are more jobs, which is what we need most," said 50-year-old ice cream seller Nelson Bolivar, as he plied his trade among an effervescent opposition crowd at Gonzalez's closing rally.
His sales have been down about 40% lately, he said, but he does well at opposition events.
"Wherever the opposition is, I go and sell ice cream," said Bolivar, who added he will back Gonzalez at the polls.
Gonzalez, 74, is known for his calm demeanor and his promises that change could bring home many migrants.
He inherited the opposition mantle from Machado, 56, after a ban on her holding public office was upheld by the country's top court. Machado won a resounding win in the opposition primary last year, but has toured the country on Gonzalez's behalf.
Maduro, a 61-year-old former bus driver and foreign minister, whose face will appear on the ballot for 13 parties, says he will guarantee peace and economic growth that will make Venezuela less dependent on oil income.
Public spending has grown only slightly during the campaign, analysts say, a change from past campaigns when spending was generous.
Maduro says he has opened 70 public works projects, but many have been renovations of already-existing schools, hospitals and roads, according to events broadcast on state television.
Thousands of people came on hundreds of buses to Maduro's closing rally in central Caracas on Thursday evening, including many public sector employees.
Unlike many of the people around her, retired teacher Noris Rojas, 70, was not wearing a crisp new Maduro t-shirt.
Instead she held a worn, homemade poster of Chavez, featuring a quote from the late president: "No one said this would be easy."
"Maduro is a man who has shown spiritual strength and has been loyal to Chavez's project," she said. "There are weaknesses but he must win, it's a chance to correct part of the economic and social issues and that's a project you can't do in one day."
Maduro's bloodbath comment drew criticism from Brazilian President Luiz Inacio Lula da Silva and Brazil's electoral court and former Argentine President Alberto Fernandez both said on Wednesday they had withdrawn from acting as election observers.
Venezuela's attorney general this week denied participating in political persecution or holding political prisoners and said the elections should be peaceful.
Results could be published Sunday night or in the following days. Polls will be open between 6 a.m. local time to 6 p.m. on Sunday.
