Gunshots hit two buses in a caravan for Luiz Inacio Lula da Silva’s campaign tour in southern Brazil on Tuesday, officials in his Workers’ party said.

No one was hurt, and the former president was not in either of the two buses, which were carrying guests and journalists. Nails had also been placed along the caravan’s route, piercing the tyres of one bus, the party said.

Lula has been traveling around southern Brazil to rally support for another presidential run in October. But the former president has been convicted of corruption, and it looks increasingly likely that he will be jailed and barred from contesting the election.

In a sign of how divisive the once spectacularly popular leader has become, his caravan has been the target of protests, and his buses have previously been pelted with eggs and stones.

“If they think that that they can do away with my will to fight, they are wrong,” Lula said at a rally Tuesday night. “The day I cannot shout anymore, I will shout through your throats! The day my mind stops thinking, I will think through your minds!”

Gleisi Hoffmann, the Workers’ party president, complained in a statement that authorities had not provided enough security for the caravan and later called the attack an attempted homicide. Officials noted that Paraná state is the only one the caravan has passed through that has not provided a police escort.

“It’s not normal in a democracy that people fire on a democratic caravan,” Hoffmann told supporters on Tuesday night.

The public security minister, Raul Jungmann, called the attack unacceptable and said he would ensure that state authorities paid close attention to the investigation.