Argentine President Javier Milei on Thursday fired back at his political opponents and defended his influential sister against claims that she and other close associates profited from a bribery scheme.

Speaking in Buenos Aires, he accused rivals of orchestrating a smear campaign against him and his party.

“This week’s 'operetta' is nothing more than another item in the long list of schemes by the ‘caste',” Milei said, using his preferred term for the left-leaning Peronist opposition that has dominated politics for decades.

The crisis swirling around the government has put Milei on the defensive and threatens to sap popular support for his party just as the political maneuvering is heating up in advance of two key electoral challenges.

The most populous province of Buenos Aires will elect local councils and provincial lawmakers on Sept. 7.

And in October, the country holds national midterm elections in which Milei seeks to expand his party's minority in the opposition-controlled Congress.

The corruption scandal erupted last week when local media published leaked audio messages in which the former director of the disability agency can allegedly be heard discussing a kickback scheme in his organization.

The scheme allegedly benefited the president’s sister and closest advisor, Karina Milei, and other senior officials to the tune of up to $800,000 a month.

Milei fired the agency chief following the publication of the audio messages and authorities are investigating the recordings.

Prosecutors have not yet filed charges.

The president first broke days of an unusual silence on the issue on Wednesday, denying the allegations to a reporter during a campaign event shortly before being evacuated as protesters hurled stones at his motorcade.

AP Video shot by Cristian Kovadloff