With neither candidate getting more than 50% of the vote, the election will go to a run-off on 25 October.
Flávio Bolsonaro's success could be the latest example of a resurgence of right-wing support in Latin America.
Right-wing Flávio Bolsonaro has won the first round of Brazil's presidential election, beating left-wing President Lula da Silva, but falling short of an outright majority.
Millions of Brazilians took to the polls on Sunday for the first round of the country's presidential elections.
Polls suggest the election will be a closely run contest between the left-wing incumbent and his right-wing rival.
The Latin American country will vote for its next president, as Lula da Silva and Bolsonaro clash over sovereignty, security and ties with Washington.
Lula, who is currently in a tight presidential race against Flávio Bolsonaro, said the industry was a "cancer" that he must "remove".
Environmentalists have heavily criticised the exploratory drilling in the sea off the mouth of the Amazon.
Javier Milei spoke at a campaign rally for right-wing presidential candidate Flávio Bolsonaro, who is running against Lula.
