President Luiz Inácio Lula da Silva and Senator Flávio Bolsonaro clashed in a heated first debate Sunday evening in São Paulo, trading accusations of corruption and personal insults just days before Brazil's presidential runoff.

The debate, broadcast on Band TV, featured sharp exchanges on the economy, public security, health care and foreign policy. Lula, 80, labeled Bolsonaro a "habitual liar" and "thug," while alluding to alleged ties to Rio de Janeiro paramilitary groups. Bolsonaro, 45, countered by calling Lula a "clown" and warning viewers to keep distance because "my wallet could be stolen."

Both candidates revisited scandals involving each other's families. Lula pressed Bolsonaro on investigations linked to the senator and his father, former President Jair Bolsonaro. The younger Bolsonaro raised questions about one of Lula's sons and a pension fraud case.

Lula also appealed directly to imprisoned former President Jair Bolsonaro, who is serving a 27-year sentence under house arrest for a failed coup attempt after the 2022 election. "Vote for me, Bolsonaro, you know your son, you know I’m better than him," Lula said.

Bolsonaro led the first round on October 4 with 47 percent of the vote to Lula's 45 percent. Recent polls show a narrowing race, with Bolsonaro holding a slim edge around 51 percent to 49 percent in some surveys.

The candidates are scheduled to meet again in a second debate on October 23. The runoff on October 25 will determine Brazil's next president amid deep polarization, with both sides seeking to mobilize the roughly 33 million voters who abstained in the first round.