Right-wing candidate Jair Bolsonaro, who was knifed in the abdomen while campaigning on Thursday, is in serious condition, his son and a hospital spokeswoman confirmed.

Presidential candidate Jair Bolsonaro leaves an agribusiness fair in Esteio, Rio Grande do Sul state, Brazil on August 29, 2018
Presidential candidate Jair Bolsonaro leaves an agribusiness fair in Esteio, Rio Grande do Sul state, Brazil on August 29, 2018 (Reuters)

Brazil's front-running far-right presidential candidate Jair Bolsonaro was stabbed in the abdomen while campaigning on Thursday, and is in serious condition and undergoing surgery, his son and a hospital spokeswoman said.

Flavio Bolsonaro, the candidate's son, wrote on his verified Twitter account that "sadly, it was more serious than we had hoped for."

"The perforation reached part of his liver, lung and intestine," Flavio Bolsonaro wrote. "He lost a lot of blood, arrived at the hospital ... almost dead. He appears to have stabilised now. Please pray!"

A hospital spokeswoman in the city of Juiz de Fora in Minas Gerais state, where the attack took place, confirmed that Bolsonaro was undergoing surgery but provided no details on his state nor his wounds.

TRT World spoke with Brazil-based journalist Micheal Fox.

The attack on Bolsonaro is a dramatic twist in what is already Brazil's most unpredictable election since the country's return to democracy three decades ago. 

Corruption investigations have jailed scores of powerful businessmen and politicians, and alienated infuriated voters.

Numerous videos on social media showed Bolsonaro, whose far-right platform includes cracking down on crime in Latin America's largest nation, being stabbed with a knife to the lower part of his stomach. 

Attacker arrested 

Police spokesman Flavio Santiago confirmed that Bolsonaro had been stabbed and that his attacker was arrested.

Santiago confirmed Bolsonaro was taken to a hospital in Juiz de Fora, a city about 200 kilometres (125 miles) north of Rio de Janeiro.

Santiago said the attacker was identified as Adelio Bispo de Oliveira, and that he was beaten up badly by Bolsonaro supporters after the attack. More information about de Oliveira wasn't immediately available.

A statement from federal police said the candidate had bodyguards. In the videos, Bolsonaro does not appear to be wearing a protective vest.

"This episode is sad," President Michel Temer told reporters in Brasilia. "We won't have a rule of law if we have intolerance."

Second in polls

Bolsonaro, a former Army captain, is second in the polls to ex-President Luiz Inacio Lula da Silva, who has been barred from running but continues to appeal.

Despite being a congressman since 1991, Bolsonaro is running as an outsider ready to upend the establishment.

While he has a strong following, Bolsonaro is also a deeply polarising figure. 

He has been fined, and even faced charges, for derogatory statements toward women, blacks and gays.

He also speaks nostalgically about the country's 1964-1985 military dictatorship and has promised to fill his government with current and former military leaders. His vice presidential running mate is a retired general.

Earlier this week, Bolsonaro said during a campaign event that he would like to shoot corrupt members of the Workers' Party.

The comment prompted an immediate rebuke the attorney general, who asked Bolsonaro to explain that comment.

Other candidates quickly denounced the attack.

"Politics is done through dialogue and by convincing, never with hate," tweeted Gerado Alckmin, former governor of Sao Paulo who has focused negative ads on Bolsonaro.

Fernando Haddad, who is expected to take da Silva's place on the Workers' Party's ticket, called the attack "absurd and regrettable."

Source: TRTWorld and agencies