New Delhi, Sept. 25 -- BRASILIA - A minute-long television advertisement broadcast Thursday accuses the president of the United States of trying to turn Brazil back into a colony, a charge Luiz Inacio Lula da Silva's campaign is now making explicitly rather than by implication.

"Flavio Bolsonaro is Trump's candidate, and what Trump wants is to colonize Brazil, take our riches, steal our future and leave us in the dust," a narrator tells viewers in the ad, which aired as Lula and his far-right rival sit essentially tied in the polls nine days before the first round of voting on Oct. 4. Lula, seeking a fourth term, wrote on social media the same day that Bolsonaro wants to "hand our natural resources over to the United States" and that "if...