Brazil's top electoral court gave U.S. social media giant Meta 24 hours to prove it is treating President Luiz Inacio Lula da Silva and his right-wing opponent, Flavio Bolsonaro, equally.
The order came on Monday after Lula's campaign alleged that Meta, which owns Facebook, WhatsApp and Instagram, is suppressing his online content to boost Bolsonaro ahead of Sunday's runoff election.
Meta has denied taking any actions to favor one side in the election, but previously said that some of Lula's campaign ads had been mistakenly deactivated due to technical errors not isolated to Brazil.
Lula's campaign has also alleged inconsistencies on WhatsApp's artificial intelligence tool, saying Lula-related election content had been limited while Bolsonaro content was untouched.
On Thursday, a judge from the Superior Electoral Court ordered Meta to ensure the same rules were applied to both candidates through the runoff election, among other directives, with a potential daily fine of $100,000 for noncompliance.
The ruling on Monday said that Meta had failed to demonstrate compliance with the order and increased the penalty to $200,000 per day, according to a court document seen by Agence France-Presse (AFP).
"The continued noncompliance, just a few days before the runoff election, demonstrates that the fine imposed was insufficient," it said.
Lula's political party, which has filed complaints with the Organization of American States (OAS) and with the United Nations Special Rapporteur on freedom of expression, reported fresh technical issues on Monday.
"We hope Meta stops benefiting Flavio Bolsonaro's campaign," party communications secretary Eden Valadares told reporters, adding that another complaint would be filed with the electoral court.
Dozens of Lula supporters protested outside the company's Sao Paulo offices, bearing placards and chanting slogans like "Meta out of Brazil."
"I hardly trust anything I see lately on Meta-run platforms," video animator Lilian Doring, 47, told AFP.
Bolsonaro, the son of jailed ex-leader Jair Bolsonaro, is the favorite to win Sunday's runoff after coming out on top in the first round earlier this month.
On Saturday, his campaign alleged a "negative propaganda offensive" driven by Lula "with the approval" of Meta.
Polls predict a technical tie between the 45-year-old senator and the current president on the cusp of 81.