A Brazilian Supreme Court justice has blocked efforts by Rio de Janeiro's conservative mayor to have a book fair remove a comic book showing two men kissing.

Mayor Marcelo Crivella had ordered the Bienale to remove the "Avengers" comic that included the kiss, saying he was acting to protect children against "sexual content."

That set off a legal battle as federal Attorney General Raquel Dodge challenged the move by Crivella, a former evangelical pastor. She said allowing the mayor to remove books goes against freedom of expression and the free exchange of ideas.

A lower court sided with Crivella. But chief justice Jose Dias Toffoli ruled in favor of Dodge on Sunday, blocking the mayor from removing any books. Crivella's office said he will appeal to the full court.