Judge orders arrest over alleged Lady Gaga concert plot

A Brazilian judge has ordered the arrest of a man suspected of being involved in an alleged plot to place explosives at a free concert by US pop singer Lady Gaga in Rio de Janeiro.

Judge Fabiana Pagel of the Rio Grande do Sul state court did not name the suspect in Monday's ruling, but said he is a man investigated by Rio de Janeiro police as the alleged mastermind of the plot.

Police in Rio Grande do Sul state, which borders Argentina and Uruguay, said they had released a man under investigation for the alleged plot after he paid his bail.

Brazilian media reported that it is the same man jailed on Monday by the judge.

Rio police did not reveal the names of either of its two suspects or show images of the explosives the alleged plotters intended to use.

Felipe Cury, secretary of the Rio police, said authorities believed the suspects sought to target Brazil's LGBTQ community.

The Rio event on Saturday was the biggest show of the pop star's career, attracting an estimated 2.5 million fans to Copacabana Beach.

Security was tight with 5200 military and police officers deployed to the beach where fans were revelling.