RIO DE JANEIRO (AP) — Police in Brazil said on Sunday that two people have been arrested in connection with an alleged plot to detonate explosives at a free Lady Gaga concert in Rio de Janeiro.

The Rio event on Saturday was the biggest show of the pop star’s career that attracted more than 2 million fans to Copacabana Beach and had crowds screaming and dancing along.

Even as Brazilian authorities said they arrested suspects in the hours before Lady Gaga’s show, the event went ahead without disruption — leading some to question the seriousness of the threat. Serious security concerns typically lead organizers to cancel such massive events — as happened with Taylor Swift’s concerts in Vienna last year.

Police said said nothing about the alleged plot at the time to in an effort to “avoid panic” and “the distortion of information.”

On Sunday, a spokesperson for Lady Gaga said the pop star and her team “learned about this alleged threat via media reports this morning. Prior to and during the show, there were no known safety concerns, nor any communication from the police or authorities to Lady Gaga regarding any potential risks.”

The statement added: “Her team worked closely with law enforcement throughout the planning and execution of the concert and all parties were confident in the safety measures in place.”

Security was tight at Saturday’s concert, with 5,200 military and police officers deployed to the beach where fans were reveling in the pop singer’s classic hits like “Born This Way,” which became something of an LGBTQ anthem after its 2011 release.

Rio de Janeiro’s state police and Brazil’s Justice Ministry presented the bare outlines of a plot that they said involved a group that promoted hate speech against the LGBTQ+ community, among others, and had planned to detonate homemade explosive devices at the event.

“The plan was treated as a ‘collective challenge’ with the aim of gaining notoriety on social media,” the police said. The group, it added, disseminated violent content to teenagers online as “a form of belonging.”

Homes in several states raided

Authorities arrested two people in connection with the alleged plot — a man described as the group’s leader in the southern state of Rio Grande do Sul on illegal weapons possession charges, and a teenager in Rio on child pornography charges. Police did not elaborate on their exact roles in the plot or on how the group came to target Lady Gaga’s free concert.

“Those involved were recruiting participants, including teenagers, to carry out integrated attacks using improvised explosives and Molotov cocktails,” police said.

The Justice Ministry said that it determined the group posed a “risk to public order.” It said the group falsely presented themselves online as “Little Monsters” — Lady Gaga’s nickname for her fans — in order to reach teenagers and lure them into “networks with violent and self-destructive content.”

The ministry said there was no impact on those attending the open-air concert.

During a series of raids on the homes of 15 suspects across several Brazilian states, authorities confiscated phones and other electronic devices. Although police said they believed homemade bombs were intended for use in the planned attack, there was no mention of the raids turning up any weapons or explosive material.

‘Historical moment’

Lady Gaga has expressed gratitude for the enormous crowd in an Instagram post that said nothing of the alleged plot.

“Nothing could prepare me for the feeling I had during last night’s show—the absolute pride and joy I felt singing for the people of Brazil,” she wrote. “The sight of the crowd during my opening songs took my breath away. Your heart shines so bright, your culture is so vibrant and special, I hope you know how grateful I am to have shared this historical moment with you.”

Her free beach concert stood out at a time of surging ticket prices for live music around the world as concert-goers pay budget-busting costs to see their favorite artists.

Rio has done this before — last May, superstar Madonna performed the finale to her latest world tower for some 1.6 million fans on the sprawling sands of Copacabana Beach.