Brazil: A supporter of right-wing Brazilian President Jair Bolsonaro stabbed a supporter of former President Luiz Inácio Lula da Silva in the latest sign of escalating political tensions ahead of the upcoming election, officials said on Friday.

Violence erupted in the west-central state of Mato Grosso, after a dispute over voting for two candidates erupted. In an election climate with intense polarization, Bolsonaro is trailing Lula in the polls.

According to the police report of the incident, 24-year-old Rafael Silva de Oliveira stabbed 42-year-old Benedito Cardoso dos Santos to death. The accused was brought to the police station, where he was arrested after confessing.

Lula addressed the stabbing incident at Friday's press conference in Rio de Janeiro, saying that "there is an atmosphere of hatred in the election process that is completely unusual."

Police should investigate whether such incidents were "ordered, or directed, or if this is a political tactic," Lula said.

He did not provide any evidence to support his claim that the attacks were planned.

According to Juanita Goeberts Estrada, director of Human Rights Watch for the Americas, the assassination of Cardoso dos Santos should be strongly condemned by all candidates.

She also said that "Brazilians deserve peaceful elections and should be able to engage in political discussions without fear of violence or retaliation for their views."

There was no immediate response from the President's Office for comment inquiry.

A similar incident occurred in July when a federal prison guard shot and killed a local Lula Workers' Party official while shouting in support of Bolsonaro.

A Bolsonaro supporter, who suffered a head injury on Friday, claimed he was attacked by supporters of the Workers' Party while they waited for Lula to attend an evangelical meeting in the state city of So Goncalo. 

Bolsonaro, who has long held prison terms against Lula and his left-wing allies, has stoked any electoral losses, including baseless allegations of electoral fraud and issues with Brazil's widely regarded electronic voting system.

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