Brazil’s front-running far-right presidential candidate Jair Bolsonaro has been stabbed in the abdomen while campaigning and is in a serious condition, his son says.

Flavio Bolsonaro, the candidate’s son, wrote on his verified Twitter account that “sadly, it was more serious that 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!”

Mr Bolsonaro’s running mate, General Hamilton Mourao, said the candidate had undergone “successful” surgery.

The attack on Mr 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 resulted in the jailing of scores of powerful businessmen and politicians, and alienated infuriated voters.

The Federal Police said in a statement that it had officers escorting Mr Bolsonaro at the time of the knife attack and the “aggressor” was caught in the act.

It said the circumstances were being investigated.

Local police in Juiz de Fora, where the attack happened, confirmed that a suspect was in custody, but they did not identify him.

Motivation not yet known

“We do not know if it was politically motivated,” Corporal Vitor Albuquerque, a spokesman for the local police, said.

TV images show Mr Bolsonaro being carried on someone’s shoulders in the middle of a crushing crowd of cheering supporters on one of the city’s main streets when a knife was seen raised above heads just before it plunged into the candidate’s body.

The pictures show Mr Bolsonaro appearing to scream in pain, then falling backward into the arms of those around him.

It took a few moments for the crowd to realise what happened, but they quickly rushed the candidate out of the street.

Mr Bolsonaro, who has spent nearly three decades in Congress, is a law-and-order candidate who routinely says that Brazilian police should kill suspected drug traffickers and other criminals at will.

He has openly praised Brazil’s military dictatorship and in the past said it should have killed more people.

Mr Bolsonaro faces trial before the Supreme Court for speech that prosecutors said incited hate and rape. He has called the charges politically motivated.

Fernando Haddad, who will likely be the leftist Workers Party presidential candidate, said the stabbing was a “shame” and a “horror”.

President Michel Temer and Mr Bolsonaro’s electoral rivals Ciro Gomes, Marina Silva, and Geraldo Alckim all expressed outrage at the attack.

– ABC