Socialist candidate Louis Ars is already receiving congratulatory messages.
“We have to lead the opposition and we will make Bolivia proud,” Mesa said on Twitter on Monday morning. He also thanked the voters who supported him.
The country’s interim president, Jeanine Ages, says the results so far show that Ars has won.
“We do not yet have an official figure, but from the data we have, Mr. Ars et al [vice-presidential candidate] Mr. [David] Chokhuwanga has won the election. I congratulate the winners, ”Ages said on Twitter.
Ars, who is leading the race, represents the movement for socialism, a party led by former President Evo Morales that is currently in exile in Argentina. Arles, who was chosen by Morales as his successor, has previously served as the country’s finance minister.
Mesa, who leads the Bolivian Citizen Social Party, was his closest rival.
According to Bolivia’s election rules, a candidate needs at least 40% of the vote to win, 10% ahead of his opponent to win the first round.
Less than 20% of the votes are officially counted, and it may take a few days for the winner of the election to be formally announced. Unofficial exit polls suggest Ars has a strong lead in seeking the presidency.
The economy is also struggling. Unemployment has risen since the epidemic began, with the International Monetary Fund forecasting a nearly 8% drop in GDP this year, and last month, US credit rating agency Moody’s downgraded Bolivia.
Meanwhile, former President Morales, who has been living in Buenos Aires since leaving Bolivia amid allegations of voter fraud last year, has expressed a desire to return to Bolivia.
Speaking to CNN, Morales said: “Sooner or later we will return to Bolivia,” he said, adding that his return was “a matter of time”.