President Jair Bolsonaro called Brazil’s bicentennial Wednesday a chance to celebrate the nation’s history, but critics say he has transformed what should be a day of unity into a campaign event and fear he will use it to undermine next month’s election in Latin America’s biggest democracy.

Bolsonaro, who trails in polls before the October 2 presidential vote, had urged Brazilians to flood the streets, and tens of thousands of his supporters turned out for a rally in Brasilia, with similar crowds expected for a show of strength in Rio de Janeiro.

The armed forces were putting on military displays in both cities, with Bolsonaro attending.

The far-right nationalist has for years made a mission of encouraging Brazilian patriotism, and coopted the national colours of green and yellow as his own. He stacked his administration with military officers and repeatedly sought their support, most recently to cast doubt on the reliability of the nation’s electronic voting system.

His attacks on the voting system have prompted widespread concern among his opponents that he may follow former US President Donald Trump’s footsteps in rejecting election results.

Bolsonaro arrived at the day’s first event, the military display in Brasilia, accompanied by at least one of the business executives who allegedly participated in a private chat group that included comments favouring a possible coup and military involvement in politics, and who is being investigated by Federal Police for possibly financing anti-democratic acts.

The crowd, decked out in green and yellow, chanted against former President Luiz Inacio Lula da Silva, the poll frontrunner who is seeking to return to the post he held in 2003-2010. Speaking at a rally immediately afterward, Bolsonaro made no reference to Brazil’s struggle for independence and instead focused on his achievements while slamming da Silva’s Workers’ Party.