Bolivia's President Evo Morales speaks during a press conference in La Paz, Bolivia, Thursday, Oct. 24, 2019. Morales declared himself the winner of the country's presidential election, saying he received the 10 percentage point lead over his nearest rival needed to win in the first round of voting. (AP Photo/Juan Karita)

LA PAZ, Bolivia (AP) — President Evo Morales on Thursday declared himself victor of the weekend election, stirring more anger among his opponents who have protested for days claiming fraud in the vote count, while the U.S., Brazil, Argentina and Colombia joined in calling for Bolivia to hold a runoff between the incumbent and his top challenger.

Electoral authorities, meanwhile, announced late in the day that voting would have to be held again in five spots in the Amazonian Beni region because of irregularities in Sunday's vote. They said the re-votes to be held Nov. 3 wouldn't change the outcome, but the development still added to the unrest over a long, contentious tally of ballots.

With 99.99% of votes counted, Morales had 47.07% to 36.51% for former President Carlos Mesa, who finished second in the nine-candidate field. That gave Morales a 10.56-point lead, a little more than a half point over the threshold he needed to win an outright victory and avoid a second-round ballot in December probably against a united opposition.

"We won in the first round," Morales declared at news conference early in the day, after he first edged over the threshold during the night. The president, the region's longest-serving leader who is seeking a fourth consecutive term, said he was bolstered by the rural vote.

Morales later backtracked a bit, saying he would be open to a runoff if he fell short of the 10-point lead when official totals were announced.

A communique issued by Colombia's foreign ministry on behalf of the U.S., Brazil and Argentina said the governments of the four nations "will only recognize results that reflect the will of the Bolivian people."

The European Union took a similar stand, saying it backed a call by the Organization of American States for a second-round election that could help Bolivia regain its footing after days of sometimes violent protests by opposition supporters angered by the slow vote count and an unexplained 24-hour halt in the release of results.

"The European Union shares the OAS' assessment that the best option would be to make a runoff to restore trust and ensure full respect for the democratic elections of the Bolivian people," the EU said in a statement that also called for the parties to refrain from further violence.

There was no comment from Morales about the outsiders' questions on the fairness of the election's opening round.

Opposition leaders were united in rejecting Morales' victory claim as the president's supporters were out celebrating. Analysts have said a united opposition might stand a chance in a second round of defeating Morales, a leftist former coca-growers union leader who has governed the Andean nation for 14 years.

Flanked by other opposition leaders, Mesa read a statement calling for "citizens and social groups to remain peacefully mobilized until they obtain respect for the will of the people."

Morales, in turn, urged his supporters to defend his win and denied electoral fraud, demanding his detractors show proof.

"We are at the start of a crisis that could affect the social, political and economic stability of the country," said political analyst Jorge Dulón at Bolivian Catholic University.

The Andean nation has been on a knife-edge since the bitterly disputed vote.

Opposition backers have stage rowdy protests since Monday and burned Supreme Electoral Tribunal offices in three cities. The opposition bastion of Santa Cruz has seen two days of a partial strike "in defense of the vote and democracy."

On Thursday, Morales supporters announced marches in the coca-growing region of Chapare, a bastion of support for the president.

International vote monitors have questioned the early daylong gap in reporting results before a sudden spurt in Morales' vote percentage. An OAS observer mission released a statement expressing its "concern and surprise over the drastic change and difficult to justify tendency in the preliminary results."

Morales had repeatedly said since late Sunday that he won the vote outright and that his opponents are conspiring to oust him.

Suspicions of electoral fraud rose when officials abruptly stopped releasing results from the quick count of votes hours after the polls closed Sunday. Morales was leading at the time, but also falling several percentage points short of the 10-ppoint edge he needed to avoid being forced into a runoff for the first time in his four election contests.

Twenty-four hours later, the electoral body suddenly released an updated figure, with 95% of votes counted, showing Morales just 0.7 percentage point short of the 10-point advantage. Since then, results have slowly been updated.

Morales, 59, a native Aymara from Bolivia's highlands, became the country' first indigenous president in 2006 and easily won the two following elections amid more than a decade of a commodities-fed economic boom in South America's poorest country. He paved roads, sent Bolivia's first satellite to space and curbed inflation.

But he has faced growing dissatisfaction, especially over his refusal to accept the results of a 2016 referendum to keep limits on presidential terms. The country's top court, considered by critics as friendly to the president, ruled that limits would violate Morales' political rights as a citizen.

Protesters run amid tear gas fired by police during a demonstration against the reelection of President Evo Morales outside the top electoral court during the wait for final results from last weekend's presidential election in La Paz, Bolivia, Thursday, Oct. 24, 2019. Morales declared himself the outright winner Thursday of an election in which he was seeking a fourth term as president, enraging his opponents who alleged vote fraud and called for further protests to demand a second round of voting. (AP Photo/Juan Karita)
A protester kicks police shields during a protest against the reelection of President Evo Morales outside the top electoral court during the wait for final results from last weekend's presidential election in La Paz, Bolivia, Thursday, Oct. 24, 2019. Morales declared himself the outright winner Thursday of an election in which he was seeking a fourth term as president, enraging his opponents who alleged vote fraud and called for further protests to demand a second round of voting. (AP Photo/Juan Karita)
Anti-government protesters march with a giant national flag demanding a second round for the presidential race, in La Paz, Bolivia, Thursday, Oct. 24, 2019. Bolivia's Evo Morales declared himself the outright winner Thursday of an election in which he was seeking a fourth term as president, enraging his opponents who alleged vote fraud and called for further protests to demand a second round of voting.(AP Photo/Juan Karita)
Anti-government protesters march demanding a second round presidential election, in La Paz, Bolivia, Thursday, Oct. 24, 2019. Bolivia's Evo Morales declared himself the outright winner Thursday of an election in which he was seeking a fourth term as president, enraging his opponents who alleged vote fraud and called for further protests to demand a second round of voting.(AP Photo/Juan Karita)
Accompanied by Gustavo Pedraza, left, Vice-Presidential candidate of the Comunidad Ciudadana party and Shirley Franco, right, Vice-President candidate of the Bolivia Dijo No party, opposition presidential candidate Carlos Mesa, center, reads a statement from opposition parties in the wake of President Evo Morales' declaring himself the outright winner of the country's presidential election, in La Paz, Bolivia, Thursday, Oct. 24, 2019. Morales victory declaration would give him a fourth straight term, after a vote that has sparked days of protests by both his opponents and supporters over accusations of fraud. (AP Photo/Juan Karita)
Presidential candidate Carlos Mesa arrives to read a statement from opposition parties in the wake of President Evo Morales' declaring himself the outright winner of the country's presidential election, in La Paz, Bolivia, Thursday, Oct. 24, 2019. Morales victory declaration would give him a fourth straight term, after a vote that has sparked days of protests by both his opponents and supporters over accusations of fraud. (AP Photo/Juan Karita)
Bolivia's President Evo Morales speaks during a press conference in La Paz, Bolivia, Thursday, Oct. 24, 2019. Morales declared himself the winner of the country's presidential election, saying he received the 10 percentage point lead over his nearest rival needed to win in the first round of voting. (AP Photo/Juan Karita)
Protesters stand amid tear gas fired by police during a protest against the reelection of President Evo Morales outside the top electoral court during the wait for final results from last weekend's presidential election in La Paz, Bolivia, Wednesday, Oct. 23, 2019. Morales said Wednesday his opponents are trying to stage a coup against him as protests grow over a disputed election he claims he won outright, while a nearly finished vote count had him teetering on the threshold between getting the win or having to go to a runoff. (AP Photo/Juan Karita)
Police stand guard outside the top electoral court where protesters who are against the reelection of President Evo Morales wait for the final results of last weekend's presidential election in La Paz, Bolivia, Wednesday, Oct. 23, 2019. Morales said Wednesday his opponents are trying to stage a coup against him as protests grow over a disputed election he claims he won outright, while a nearly finished vote count had him teetering on the threshold between getting the win or having to go to a runoff. (AP Photo/Juan Karita)
A female supporter of Bolivian President Evo Morales shows her support during a march in La Paz, Bolivia, Wednesday, Oct. 23, 2019. Morales said Wednesday his opponents are trying to stage a coup against him as protests grow over a disputed election he claims he won outright, though a nearly finished vote count suggests it might head to a second round. (AP Photo/Juan Karita)