More than three weeks after losing a re-election bid, Brazilian leader Jair Bolsonaro has blamed a software bug and demanded that the electoral authority annuls votes cast on most of Brazil’s electronic voting machines.

Although independent experts say the bug does not affect the reliability of results, such an action would leave Mr Bolsonaro with 51% of the remaining valid votes – and a re-election victory, according to lawyer Marcelo de Bessa, who filed a 33-page request on behalf of the President and his Liberal Party.

The electoral authority has already declared victory for Mr Bolsonaro’s nemesis, leftist former president Luiz Inacio Lula da Silva, and even many of the President’s allies have accepted the results.

Protesters in cities across the country have steadfastly refused to do the same, particularly with Mr Bolsonaro declining to concede.

Liberal Party leader Valdemar Costa and an auditor hired by the party told reporters in Brasilia that their evaluation found all machines dating from before 2020 – nearly 280,000 of them, or about 59% of the total used in the October 30 run-off – lacked individual identification numbers in internal logs.

Neither explained how that might have affected election results, but said they were asking the electoral authority to invalidate all votes cast on those machines.

The complaint characterised the bug as “irreparable non-compliance due to malfunction” that called into question the authenticity of the results.

Immediately afterward, the head of the electoral authority issued a ruling that implicitly raised the possibility that Mr Bolsonaro’s own party could suffer from such a challenge.

Alexandre de Moraes said the court would not consider the complaint unless the party offers an amended report within 24 hours that would include results from the first electoral round on October 2, in which the Liberal Party won more seats in both congressional houses than any other.

Creomar de Souza, political analyst of Dharma Political Risk and Strategy, said the wording of Mr de Moraes’ ruling indicates the electoral court is likely to reject the appeal.

The bug had not been known previously, yet experts said it also does not affect results. Each voting machine can still be easily identified through other means, like its city and voting district, according to Wilson Ruggiero, a professor of computer engineering and digital systems at the Polytechnic School of the University of Sao Paulo.

Mr Bolsonaro’s less than two-point loss to Mr da Silva on October 30 was the narrowest margin since Brazil’s 1985 return to democracy.

While the President has not explicitly cried foul, he has refused to concede defeat or congratulate his opponent – leaving room for supporters to draw their own conclusions.

Many have been protesting relentlessly, making claims of election fraud and demanding that the armed forces intervene.

Dozens of Bolsonaro supporters gathered outside the news conference on Tuesday, decked out in the green and yellow of Brazil’s flag and chanting patriotic songs. Some verbally attacked and pushed journalists trying to enter the venue.

Mr Bolsonaro spent more than a year claiming Brazil’s electronic voting system is prone to fraud, without ever presenting evidence.

The president’s son, federal legislator Eduardo Bolsonaro, repeated that concern at a conference in Mexico last week.

Brazil began using an electronic voting system in 1996, and election security experts consider such systems less secure than hand-marked paper ballots because they leave no auditable paper trail.

But Brazil’s system has been closely scrutinised by domestic and international experts who have never found evidence of it being exploited to commit fraud.

The senate’s president, Rodrigo Pacheco, said on Tuesday afternoon that the election results are “unquestionable”.

In a separate report presented earlier this month, the Brazilian military said there were flaws in the country’s electoral systems and proposed improvements, but did not substantiate claims of fraud from some of Mr Bolsonaro’s supporters.

Analysts have suggested that the armed forces, which have been a key component of Mr Bolsonaro’s administration, may have maintained a semblance of uncertainty over the issue to avoid displeasing the President.

In a subsequent statement, the defence ministry stressed that while it had not found any evidence of fraud in the vote counting, it could not exclude that possibility.