Left-wing government candidate Claudia Sheinbaum is poised to become Mexico's first female president, in an historic election overshadowed by violence, according to preliminary results.
Frontrunner Sheinbaum, a former mayor of Mexico City, garnered between 58.3 and 60.7% of the votes, well ahead of her main challenger Xóchitl Gálvez, the electoral authority of the world's most populous Spanish-speaking country said on Sunday evening.
Gálvez came in second with 26.6 to 28.6%, the authority said after ballots from some 5,600 polling stations had been counted.
The announcement of preliminary results had been postponed several times, without a reason given by the authority.
"They are lying as always," Gálvez, who was backed by a broad alliance of Mexico's three main opposition parties, wrote on X before the first results were released.
Sheinbaum, 61, from the ruling Morena party is set to take office on October 1.
A trained scientist, she is considered a long-time ally of incumbent left-wing populist President Andrés Manuel López Obrador, who is not allowed to run again after six years in office.
Gálvez, a businesswoman, computer engineer and former senator, was backed by the broad centrist opposition alliance Strength and Heart for Mexico, formed by the National Action Party (PAN), the Institutional Revolutionary Party (PRI) and the Party of the Democratic Revolution (PRD).
A third candidate, Jorge Álvarez Máynez from a smaller party, was seen as having no chance.
To win the election, a simple majority is enough.
Alongside the presidency, Mexicans voted to fill all seats in the Chamber of Deputies, the Senate plus regional and municipal posts, making it an election day of historic proportions.
In total, more than 20,000 offices were up for grabs, including governorships in eight of the 31 federal states and in the capital district.
Almost 100 million citizens were entitled to vote.
The campaign period was overshadowed by violence, with at least 34 candidates killed since the application phase opened in September, according to data from consultancy Integralia. Officials say criminal groups warring for influence in some regions are behind many of these attacks.
At least three people were killed in violent incidents at separate polling stations in the states of Puebla, México and in the outskirts of Monterrey on election day, according to media reports.
In the central state of Puebla, a polling station in the municipality of Tlapanalá was unable to open after the ballots had been stolen, according to the electoral authority.
In the town of Coyomeapan, voting had to be interrupted due to violence.
In the cities of Chicomuselo and Pantelhó in the southern state of Chiapas, the elections were completely suspended due to the violence of the drug cartels in the region.