RIO DE JANEIRO — Supporters of Jair Bolsonaro have held their first campaign rally since the right-wing Brazilian presidential candidate was stabbed and seriously wounded.

About 300 people gathered at Rio de Janeiro's Copacabana beach, summoned by tweets from the candidate's son Flavio, who told the crowd that the attack "will not go unpunished."

Limited advance notice and competition from beachside activities may have restricted the crowd, despite intense news coverage of Thursday's attack. Bolsonaro himself may not be able to campaign ahead of the Oct. 7 vote. He's leading in polls now that former President Luiz Inacio Lula da Silva has been disqualified for a corruption conviction.

A man named Adelio Bispo de Oliveira has been accused of attacking Bolsonaro and has been transferred to a federal prison. His motive isn't yet clear.