In this Thursday, May 27, 2010 file photo Russian gay activist Nikolai Alexeyev speaks at a news conference in Moscow, Russia. Nikolay Alexeyev, a prominent Russian gay activist says he's been fined an equivalent of $170 for "gay propaganda" among minors in the first ruling of this kind in Russia's modern history. Alexeyev said Friday, May 4, 2012, a city court in St. Petersburg fined him 5,000 rubles ($170). He pledged to appeal the decision.  (AP Photo/Alexander Zemlianichenko, file)

Fined ... Nikolai Alexeyev. Photo: AP

A PROMINENT Russian gay rights activist has been convicted of spreading ''gay propaganda'' among minors in the first such ruling in Russia's modern history.

Nikolai Alexeyev said that a city court in St Petersburg fined him 5000 rubles ($166) for breaching the law, which was controversially introduced by MPs in Russia's second-largest city in February. He pledged to appeal against the decision.

Gay rights activists say the legislation could be used to ban public demonstrations.

Alexeyev was briefly detained last month after he picketed the city hall in St Petersburg with a poster that said that ''homosexuality is not a perversion''.

He said the judge has not presented the grounds for her decision and that they will only be available next week. Calls to the court went unanswered shortly after the ruling.

Homosexuality was decriminalised in Russia in 1993, but anti-gay sentiment remains strong.

Alexeyev said he would go to Russia's Constitutional Court and then to the European Court of Human Rights if a higher court in St Petersburg upholds Friday's ruling.

Yuri Gavrikov, of St Petersburg's gay lobby group Equality, described the ruling as ''absurd''.

''There were no children where Alexeyev held his picket,'' he said, adding that the wording of the law used in the activist's case was vague.

Associated Press