Police in Moscow have detained around 60 people at a rally held by Russia's Kremlin-friendly Communist Party, according to the organisation.
A party statement said the arrests took place as the event was ending on Sunday, with its Moscow branch trying to secure the release of detainees, who were mostly young people.
The gathering marked the anniversary of the Kremlin's 1993 crushing of a parliamentary uprising.
Telegram news channel Ostorozhno Novosti said protesters chanted slogans including "Freedom for political prisoners," "For fair elections," and "Down with the Tsar."
The rally came as public frustration has been simmering in Russia during the intensifying Ukrainian drone attacks deep inside the country. The strikes have hit oil refineries and warehouses, caused fuel shortages and disrupted daily life, including in Moscow.
The October 1993 violence capped a long standoff between President Boris Yeltsin and hard-line lawmakers who opposed his painful free-market reforms. After Yeltsin ordered parliament disbanded and demonstrators supporting the lawmakers tried to seize the state TV broadcasting center, he sent in the military, which used tanks to shell the parliament building. Authorities said 123 people were killed, while unofficial estimates put the toll in the hundreds.
The Communist Party has been a leading force in parliament since the 1990s, led for more than three decades by 82-year-old Gennady Zyuganov, a former Soviet official.
Throughout Putin's rule of over a quarter-century, the Communists have criticized some aspects of government policy but carefully avoided any criticism of him. They steadfastly support the war in Ukraine.
Meanwhile, Ukrainian President Volodymyr Zelensky said on Sunday that Putin is trying to weaken Ukrainian resistance with an escalation in air strikes against the capital Kyiv and other cities.
"They strike bridges — do they really think we will not respond? I am simply astonished by this animalistic desire to escalate the situation every day," Zelenskiy told a news conference, alongside German Chancellor Friedrich Merz.
"Putin wants to weaken Ukraine's resilience as much as possible," Zelenskiy added, noting Russia was trying to get residents to leave Ukraine's major cities.
US peace envoys are trying to organize a trilateral, technical-level meeting by the end of October, Zelensky added, saying that Ukraine was open to gathering in the UAE or other countries.
