(CNN) An Avengers comic book featuring a kiss between two male superheroes has sold out at a Rio de Janeiro book fair after the city's conservative mayor attempted to block it from sale, according to Agence France-Presse.

Marcelo Crivella, mayor of Rio de Janeiro, said the comic's depiction of a kiss between two men was "unsuitable for minors."

Crivella, who called homosexuality a "terrible evil" in his 1999 book "Evangelizing Africa," objected to a kiss depicted between the superheroes Wiccan and Hulkling. By Friday, the comic had completely sold out at the book fair, organizers told AFP.

"Guys, we need to protect our children," the mayor wrote on Twitter. "As a result, we have determined that the Biennial organizers collect books with content that is unsuitable for minors. It is not right for them to have early access to subjects that are not appropriate for their ages."

After his demand sparked backlash, he said in a subsequent tweet : "The decision to collect comic books at the Biennial had only one goal: to comply with the law and protect families. According to ECA (Brazil's Child and Adolescent Statute), the works should be sealed and identified as to their content. In this particular case, there was no warning on the subject matter."

In a video posted on Twitter, Crivella, who was elected in 2016, said, "There's a certain controversy in the media regarding the Mayor's decision of removing the books that had homosexual content which reached a childish, juvenile audience. What we did was to protect the families, this should be a matter discussed within the families. It can't be induced, be it at schools, book sessions, wherever it may be. We will always look to protect families."

The organizers of the book fair responded by filing a preventive injunction with Rio de Janeiro's Court of Justice Friday. In a statement posted on Instagram, the organizers said the injunction was intended to "ensure the full operation of the event and the right of exhibitors to market literary works on the most diverse themes -- as foreseen by the Brazilian legislation."

The Book Biennial, which is billed as the largest literary event in the country, "keeps its schedule for the weekend, giving voice to all audiences, without distinction, as a democracy should be. This is a plural festival where everyone is welcome and represented," the statement also read.

The book fair, which concludes Sunday, will host events on topics including "happiness, science, motherhood, theater, trans literature, LGBTQA+ and more," according to the Instagram post.