Police detained dozens of people when pro- and anti-gay activists clashed in the Russian city of St Petersburg on Saturday, just two weeks after parliament passed a law banning homosexual "propaganda".
Critics say the bill - a nationwide version of laws in place in cities including St Petersburg, President Vladimir Putin's hometown, - effectively bans gay rights rallies and could be used to prosecute anyone voicing support for homosexuals.
Up to 100 people took part in the march to protest against the law, confronted by an equal number of anti-gay activists, who threw eggs, smoke flares and stones at them.
Police intervened with batons to stop the violence and detained dozens of people.
"We staged the rally to support our rights and express our protest against the homophobic law," Natalya Tsymbalova, a gay activist said by telephone from a police station, adding that the rally did not infringe Russian law.
The march was organized by the group "Ravnopraviye" (Equal Rights).
The incident highlights increasing intolerance in Russian society towards gay people and a toughening of laws aimed at stifling any dissent against the rule of Putin in general.
The bill passed by the lower house on June 11 bans the spreading of "propaganda for non-traditional sexual relations" to minors and sets heavy fines for violations. It has yet to be signed into law by Putin.
There are no official figures on anti-gay crime in Russia, but in an online poll last year, 15 percent of about 900 gay, lesbian, bisexual or transgender respondents said they had been physically attacked at least once in the previous 10 months.
Putin, who has embraced the Russian Orthodox Church as a moral authority and harnessed its influence as a source of political support, has championed socially conservative values since starting a new, six-year term in May 2012.