"He had approached the Casa Rosada with a machete and other sharp objects and PFA [Argentine Federal Police] officer Yanina Violante... stopped him," Bullrich said in a post on the X social media platform Thursday.
Citing the country's police, Argentine broadcaster TN reported that the attacker, age 29, decided to pass through a fence on the side of the government house that had been left open as an official was leaving the building.
"I am God and I will kill the president," the attacker shouted as he was detained by police.
He was found to be carrying a nearly 8-inch-long machete, five circular saw blades and a fork, the report said.
Milei has served as the South American country's leader since defeating Peronist candidate Sergio Massa in the second round of Argentina's presidential election last November. The self-proclaimed "anarcho-capitalist" has proven intensely polarizing as he attempts to pull the country out of a deep economic crisis through deregulation and cuts to the welfare state. Milei provoked further controversy earlier this year by reversing course on his predecessor Alberto Fernandez's plans for Argentina to join the BRICS economic bloc.