In the last public appearance by a Brazilian presidential candidate before Sunday's vote, left-leaning Fernando Haddad warned voters that his far-right opponent's proposals to fight crime would only increase violence.

He also promised to bring conciliation if he beats front-runner Jair Bolsonaro, who stayed in his home in Rio de Janeiro speaking to his voters via social media.

Haddad, who polls indicate is the underdog in the runoff, spoke during a rally in Heliopolis, Sao Paulo's biggest favela with more than 100,000 residents. Violent areas of big cities gave Bolsonaro less votes in the Oct. 7 first-round than safer and richer areas.

"Arming the population, like my adversary suggests, will only increase violence. Can you imagine children and women bearing guns too? My adversary's ideas have already been tested in other countries and the number of homicides only picked up," Haddad said.

Later the candidate hand-picked by jailed former President Luiz Inacio Lula da Silva said this Brazilian election would be different from any other if Bolsonaro loses at the last minute.

"That would be the victory of a project, not of a person or a party. It would be a vote for democracy and freedom," Haddad said during a discussion in social media.

Haddad suffered a blow when defeated presidential candidate Ciro Gomes, a leftist who finished the first-round in third place with 12 percent of the vote, failed to strongly support the Workers' Party candidate.

"Everybody wanted me, with my style, to pick a side and take part in the campaign," Gomes said in a video. "But I don't want to do this now for a reason that is very practical and I don't want to say it now. If I can't help, I don't want to get in the way."

Without a clear endorsement from Gomes, Haddad made a surprising nod to right-leaning defeated presidential candidate Geraldo Alckmin, saying he gave the inspiration to one of his proposals to cut cooking gas prices.