Candidate for Sao Paulo Mayor Jose Luiz Datena, left, swings a chair at his opponent Pablo Marcal during a televised debate, in Sao Paulo, Brazil, on Sunday, September 15.
CNN  — 

A mayoral debate in the Brazilian city of S?o Paulo turned ugly when one of the candidates attacked a rival with a chair.

Video from the debate, broadcast live on Sunday by TV Cultura, shows a tense exchange between José Luiz Datena and Pablo Mar?al before Datena swings the chair at his counterpart.

Datena later told TV Cultura that he had attacked Mar?al – who required hospital treatment for his injuries – because he had brought up old sexual harassment allegations against Datena that were dismissed several years ago.

“He came with a case that was archived, that was not even investigated by the police because there was no evidence. Something from 11 years ago that caused a very serious situation within my family,” Datena said.

Datena was expelled from the debate but insisted in a statement Monday that while he had made a mistake he did not regret his actions.

Mar?al was treated at Sírio Libanês Hospital before being released. His team said he was treated for a possible fracture in the chest region and had difficulty breathing. The hospital said he had suffered trauma to his chest and wrist, but without any major complications.

Mar?al compared the chair attack to the July assassination attempt against former US President Donald Trump and the stabbing of former Brazilian President Jair Bolsonaro during the 2018 election, posting an image of all three attacks on Instagram with the caption: “Why all this hate?”

The remaining candidates Guilherme Boulos, Marina Helena, Ricardo Nunes and Tabata Amaral continued the debate following the attack. TV Cultura said it regretted the incident and had pressed ahead with the discussion in accordance with the rules after the other candidates agreed.

Mar?al’s team has vowed to take legal action.

“Pablo Mar?al was cowardly attacked by José Luiz Datena, who hit him in the ribs with an iron chair,” Mar?al’s team said, adding that it was unfortunate the debate had continued without him.

CNN has reached out to S?o Paulo police as well as Datena and Mar?al’s teams.

CNN’s Michael Rios contributed to this report.