Brazilian President Jair Bolsonaro often talks about his "army," the die-hard supporters who fueled his winning campaign four years ago.

As the far-right incumbent launched his reelection bid Tuesday, trailing his leftist nemesis, ex-president Luiz Inacio Lula da Silva (2003-2010), heading into Brazil's October elections, Bolsonaro's hardline backers were front and center.

"I swear to you once again, I will give my life to defend our freedom," the 67-year-old ex-army captain told a fired-up crowd in Juiz de Fora, the southeastern city where he narrowly survived a stabbing attack in 2018.

That attack, perpetrated by a man later deemed mentally unfit to stand trial, cemented Bolsonaro's image in the minds of supporters as their "Messias," or Messiah -- his middle name.

Four years on, Bolsonaro is struggling to repair his image as a savior sent to rough up the political establishment, bruised by a series of crises including his government's disastrous handling of the coronavirus pandemic and soaring inflation.

Trailing Lula by more than 10 points in many opinion polls, Bolsonaro has increasingly been directing his anti-establishment attacks at Brazil's electronic voting system, raising fears he may refuse to accept the election result if he loses.

Many Brazilians fear if he loses, Bolsonaro could try to follow in the footsteps of his political role-model, former US president Donald Trump -- currently under investigation by a Congressional committee for his rejection of his 2020 election loss and role riling up rowdy supporters who attacked the Capitol in Washington in a bid to stop Congress from confirming the result.

With some warning a similar script could play out in Brazil, Bolsonaro's "army" is in the spotlight.

Felipe Vicente Alves, who was in the middle of the crowd at Tuesday's rally, remembers the day Bolsonaro was stabbed all too well.

"I was right here. I was following the march, and I saw everyone crowd around him, rushing to save him," said the 41-year-old insurance broker, wearing the yellow and green of the Brazilian flag.

"I spent the rest of the day praying for him."

Alves said he believes Bolsonaro will win the election in the first round, calling opinion polls "manipulated."

If things don't go his candidate's way, Alves said, he knows what to do.

"If we have to fight for our country, we'll fight -- with arms, if necessary," he told AFP.

His brother, Carlos Henrique Augusto, backs Bolsonaro, too -- but is more moderate.

"We don't want a civil war. The media have created this monster, this idea that all Bolsonaro supporters are armed and shooting at people. It's not true," he said, amid a sea of flag-waving supporters.

"We just want citizens to have the right to defend themselves."

Firearm ownership has boomed in Brazil under gun-rights advocate Bolsonaro, whose signature gesture is a pistol with his thumb and forefinger.

The number of privately owned guns in Brazil has doubled to nearly two million since 2018, according to a recent study.

"I have a gun, and I wouldn't hesitate to use it," said Bolsonaro backer Joao Vitor Ferreira, 39, who was at the president's rally with his wife and nine-year-old daughter.

Nearby, supporters of the man dubbed the "Tropical Trump" held up a banner highlighting the close ties between Bolsonaro and his former US counterpart.

"Trump 2024," it said.