Brazilian President Luiz Inacio Lula da Silva's campaign team will request the disqualification of rival Flavio Bolsonaro on Tuesday over alleged election interference by tech giant Meta, a source told AFP.
Lula is seeking a fourth non-consecutive term in office but is facing stiff competition from his right-wing challenger, the son of jailed ex-leader Jair Bolsonaro.
Flavio Bolsonaro received 47 percent of the vote over the incumbent's 45 percent in the first round earlier this month, and polls show a technical tie ahead of Sunday's runoff.
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The petition to be submitted to Brazil's top electoral court concerns alleged "algorithmic manipulation" by Meta aimed at harming Lula's chances of winning, the campaign source said.
The information was first revealed Monday by Brazilian newspaper Folha de S. Paulo.
Meta and lawyers from both campaigns will meet at the Superior Electoral Court (TSE) on Tuesday, a court source said.
Read moreBrazil's Lula, Bolsonaro clash in bitter debate ahead of election run-off
The court on Monday gave Meta 24 hours to prove it was complying with an order to treat both campaigns equally, threatening a daily fine of around $200,000 if it didn't.
The order came after Lula's campaign alleged that Meta, which owns Facebook, WhatsApp and Instagram, was suppressing his online content to boost Bolsonaro.
"We have completed the implementation of the measures to comply with the Superior Electoral Court's decision," the company stated on Tuesday.
Lula seeks fightback
Lula's campaign also alleged inconsistencies in WhatsApp's artificial intelligence tool, saying Lula-related election content was limited while Bolsonaro content was untouched.
Meta has denied taking any actions to favour one side in the election, but previously said that some of Lula's campaign ads had been mistakenly deactivated due to technical errors.
Dozens of Lula supporters protested outside the company's Sao Paulo offices on Monday, bearing placards and chanting slogans like "Meta out of Brazil".
Read moreHow Lula’s successes in Brazil may have paved the way for his presidential defeat
Lula, 80, has also accused the American government of meddling in the elections in favour of Flavio Bolsonaro.
US President Donald Trump has not yet explicitly endorsed Bolsonaro, 45, but called his surprise first-round finish a "very, very big victory".
The runoff victor will either preserve the vast country of 214 million people as a left-wing stronghold in Latin America, or usher it into the ranks of right-wing administrations loyal to Trump.
The shock result of the first round appears to have invigorated the left, with Lula's camp staging massive rallies ever since and seeking to up its social media game.
Flavio's father Jair Bolsonaro is serving a 27-year prison sentence under house arrest for attempting a coup following his electoral defeat to Lula in 2022.
Flavio Bolsonaro has sworn to liberate his father if elected.
(FRANCE 24 with AFP)