Moscow (CNN) -- Police detained about 40 gay-rights activists in Moscow on Sunday, alleging they attempted to hold an unauthorized demonstration during Moscow gay pride events, the police press service said.
State-run Russian news agency RIA Novosti reported that prominent gay rights activist Nikolai Alexeyev and several others were among those detained during an authorized picket near Moscow's city hall.
"The picket was devoted to the anniversary of the decriminalization of homosexuality in Russia and was not sanctioned by the authorities," RIA Novosti said.
Activists have held similar gay pride demonstrations in previous years, but usually disperse before police arrive, according to the news agency.
Incumbent Moscow Mayor Sergei Sobyanin and his predecessor, Yury Luzhkov, have both spoken against public gay-rights rallies, with Luzhkov calling them "Satanic," according to RIA Novosti.
An authorized gay pride rally took place in St. Petersburg for the first time May 17, the news agency said, but "dozens of unidentified thugs attacked the activists after the event, beating them up." One activist was detained, but RIA Novosti said there were no serious injuries or damages from the incident.
CNN's Arkady Irshenko contributed to this report.