Russian police on Sunday detained more than two dozen LGBT rights advocates who were taking part in May Day marches.

Elvina Yuvakaeva, a Russian LGBT rights advocate, told the Washington Blade earlier this week that a group of activists in St. Petersburg marched with another contingent in the city’s May Day parade because authorities denied their request to participate alone.

A video shows the advocates carrying a rainbow flag and chanting as they marched through a square. Several police officers and journalists then surrounded them.

Yuvakaeva told the Blade that authorities detained around 15 of them.

“Authorities prefer meetings of neo-Nazis to opposition and peaceful LGBT manifestations,” Yuvakaeva told the Blade.

“By using different pretexts they did not confirm the route for LGBT (marchers) and did not propose an alternative option as the law requires,” she added. “At the same time they found it to be fine when the Nazi organization banned in Russia goes through the city with a ‘united Slavic people and white race’ column.”

Yuvakaeva told the Blade that LGBT rights advocates received permission to participate in a separate May Day march in Moscow.

A video shows police officers ripping rainbow flags from the activists as they marched. A series of scuffles broke out before the authorities forcibly removed them from a park.

A group of young men chanted “Moscow is not Sodom” as the officers placed the activists into awaiting police vans.

A State Department official criticized the activists’ detentions.

“We are troubled by reports that LGBTI activists were banned from participating in May Day events, including in St. Petersburg, and that Russian police detained more than a dozen LGBTI marchers who chose to participate despite the ban,” the official told the Blade on Tuesday in a statement.

The detentions are the latest in a series of events that underscore concerns over Russia’s LGBT rights record.

President Vladimir Putin in 2013 signed a law that bans the promotion of so-called gay propaganda to minors.

Ivan Nikitchuk and Nikolai Arefyev, who are members of the Russian Communist Party, introduced a measure last October in the Russian Duma that critics said would have effectively banned gays and lesbians from coming out. A parliamentary committee earlier this year expressed opposition to the draconian measure.

“We remain concerned by the treatment of LGBTI persons in Russia and we fundamentally disagree with the idea that diversity poses a threat to Russian or any society,” the State Department official told the Blade on Tuesday. “We believe diversity helps societies thrive.”

“We again call on Russia to uphold the fundamental freedoms of expression, peaceful assembly, and association for all citizens, regardless of sexual orientation or gender identity,” added the official.

The Kremlin has yet to return the Blade’s request for comment on the detentions.