Brazilian police said Sunday they had arrested two people in connection with a foiled plot to attack Lady Gaga's packed mega-concert in Rio de Janeiro.

Rio's civil police force said that "together with the ministry of justice" it had "prevented a bomb attack that would have occurred at Lady Gaga's concert in Copacabana" on Saturday night.

Officials said the superstar's free gig on the beach drew up to two million people.

Writing on X, Rio police said it had arrested an adult who was "responsible for the plot" as well as a teenager in the operation codenamed "Fake Monster" — a reference to Lady Gaga's pet name for her fans, "Little Monsters."

It said those involved had recruited people online to "carry out attacks using improvised explosives" in an attack "aimed at gaining notoriety on social media."

Police carried out raids across Rio de Janeiro state as well as in the states of Sao Paulo, Rio Grande do Sul, and Mato Grosso.

Lady Gaga's concert was the second million-strong stage show on Copacabana beach in a year after a huge concert last year by Madonna.

Security was extremely tight for Saturday's show, with some 5,000 officers, drones and both surveillance and facial recognition cameras deployed.