Brazilian President Luiz Inacio Lula da Silva’s campaign has accused US tech giant Meta, the parent company of Facebook and Instagram, of interfering in the country’s presidential election in favor of his right-wing rival, Flavio Bolsonaro.

In a statement on Saturday, Lula’s Workers’ Party (PT) accused Meta of repeatedly restricting its campaign activities while failing to provide convincing explanations. “The complete lack of transparency in the company’s systems makes these explanations scarce and opaque,” the statement read.

The campaign said the latest incident occurred between October 9 and 10, when Meta allegedly prevented Lula’s official Instagram account from boosting posts. It also claimed that the view count on one of Lula’s Instagram posts stopped increasing on October 8, affecting its reach, with similar problems registered on other accounts supporting the incumbent.

An internal analysis also suggested that Meta’s algorithms were skewed in favor of Bolsonaro, Lula’s campaign alleged, adding that posts on the right-wing contender’s page generated, on average, 2.96 times as much engagement as Lula’s, despite Bolsonaro having 17.2% fewer followers.

Brazil’s Superior Electoral Court subsequently ordered Meta to provide detailed technical explanations within 48 hours as well as to preserve relevant advertising data, moderation records, and audience metrics.

Meta has denied the allegations as “simply false and unsupported by the facts,” insisting that many of the technical problems were not limited to Brazil or specific accounts and that it is committed to treating all users equally.

The accusations against the US tech giant come amid a closely contested presidential race. Flavio Bolsonaro, the son of former Brazilian President Jair Bolsonaro – who is serving a 27-year prison sentence for plotting a coup following his 2022 election defeat – received 47.03% of the vote in the first round, compared with Lula’s 45.16%. The two are due to face each other in a runoff on October 25.

US President Donald Trump has described Jair Bolsonaro’s prosecution as a “witch hunt,” with Washington imposing steep tariffs on Brazilian goods. While the US leader has stopped short of endorsing Bolsonaro Jr., Lula has described him as a “Trump candidate.”

Just days before the first round of the vote, Meta blocked the advertising account on Facebook used by Lula’s campaign, preventing it from running new ads. While the account was restored within hours, Meta offered no specific explanation for the suspension.

Earlier this month, Brazilian authorities requested an investigation into alleged US funding for activities intended to interfere with the elections and undermine the Supreme Federal Court. The move followed a Guardian report claiming that the Trump administration had earmarked $1 million for a project called ‘Countering Lawfare and Censorship in Brazil’. However, Brazil’s Federal Police later closed its preliminary review, citing insufficient evidence to open a criminal investigation.

Last month, Lula’s campaign accused Trump of seeking to “colonize” Brazil in a bid to gain access to its natural resources.