Brazil's branch of Amnesty International on Sunday held a rally in Rio to protest what it termed Russia's "homophobia", AFP reports.
Ahead of the Winter Olympics, which start Friday in the Russian city of Sochi, Amnesty pledged to hand in to Russia's embassy in Brasilia a petition against Moscow legislation equating homosexuality with pedophilia.
The Brazil branch of the human rights organization said it had collected more than 6,000 signatures protesting Moscow's stance on homosexuality.
"It is absolutely inadmissible that a country which purports to play a leading role in the world today indulges in homophobic discourse," said spokesman Maurício Santoro.
The Amnesty campaign comes days after Russian President Vladimir Putin said homosexuals could feel "relaxed" about attending the Olympics but should "leave children alone, please."
A global online petition against Russia's hardline views on gays has gathered more than 405,000 signatures, on the websites of equality group All Out and Athlete Ally, which tackles homophobia in sports.
More than 50 Olympians past and present have put their names to that petition.
Following the 2012 London Games the Russian government pledged as Winter Games hosts to respect Olympic principles of non-discrimination, inclusiveness and equality.