Amnesty International says Russian authorities must prosecute those behind a violent attack at a nongovernmental gay-rights office in St. Petersburg that left two people injured on November 3.
Amnesty said in a statement the next day that two masked men with air guns and baseball bats attacked LaSky, an NGO that supports gay people living with HIV.
The St. Petersburg Prosecutor-General's Office said it has opened an investigation into hooliganism.
Denis Krivosheev, Europe and Central Asia deputy director at Amnesty International, said the attack is "sadly characteristic of a widespread atmosphere of homophobia in Russia today."
The attack occurred during a weekly gathering of some 25-30 young people.
Amnesty said one of those injured lost sight in one eye as a result of the attack.