A judge in Brazil has barred the campaign of leftist presidential candidate Luiz Inacio Lula da Silva from running an ad linking incumbent Jair Bolsonaro to cannibalism.

That ruling in the bizarre case comes as tensions mount, with a high-stakes second-round vote to pick Brazil's next president just three weeks away.

The Lula campaign spot was "out of context," Judge Paulo de Tarso Sanseverino of the Superior Electoral Tribunal said in a ruling Saturday.

The ad uses a video from 2016 when the far-right president, then a deputy, described for a New York Times interviewer what he said was a cannibalistic ritual practiced by the indigenous Yanomami community in  northern Roraima state.

"They cook it for two or three days and they eat it with bananas," he said in an extract that went viral on Brazilian social networks.

"I wanted to see the Indian get cooked. And then they tell me: 'If you see it, you have to eat it.' I eat it!"

An off-camera narrator in the campaign ad then says: "After all the absurdities Brazil has heard from Bolsonaro, here's another, even more horrifying: he reveals that he would eat human flesh. Brazil can no longer put up with Bolsonaro."

Judge Sanseverino said the interview had been edited to change its original meaning, "suggesting that the candidate could accept the possibility of consuming human flesh in any circumstance."

A Yanomami leader, Junior Hekurari, has categorically denied that his culture practices cannibalistic rituals.

Lula himself on Saturday defended the ad.

"It wasn't the Lula campaign that said this, it was he who said it, to an American journalist," said Lula, Brazil's president from 2003 to 2010. "We're just informing the people."

Tension between the two camps has been building as the second-round vote, on October 30, approaches.

Bolsonaro told reporters Friday that Lula was a "drunkard" who wanted to lead Brazil with his "gang of incompetents."

The latest Datafolha survey, published Friday, puts Lula in the lead, by 53 percent to 47 percent.