Small groups of Russians laid flowers at makeshift memorials for deceased opposition politician Alexei Navalny on Friday, despite warnings from authorities.
The 47-year-old Kremlin critic was serving a 19-year prison sentence in the Arctic when authorities announced his death, prompting fear and disbelief among his supporters.
Images on social media showed dozens of people queueing to place flowers at monuments to victims of political repression in the cities of Moscow and Saint Petersburg.
Authorities in the Russian capital said they were aware of calls online "to take part in a mass rally in the centre of Moscow" and warned people against attending.
Protests are illegal in Russia under strict anti-dissent laws, and authorities have clamped down particularly harshly on rallies in support of Navalny.
In Moscow, dozens laid red and white roses at the Solovetsky Stone, a monument to victims of Soviet-era repression opposite the headquarters of Russia's FSB security services -- the former home of the feared Soviet secret police.
At least one person was detained for holding up a placard that appeared to say "murderers" on it, according to a video posted by the independent Sota Telegram channel.
A handful of people were pictured gathering to lay flowers at a bridge next to the Kremlin where Putin critic Boris Nemtsov was killed in 2015.
Police were filmed dispersing people who had gathered in the snow at a memorial in the central city of Kazan.
Some larger demonstrations also took place in the Georgian capital Tbilisi, Armenia's capital Yerevan and the Serbian capital Belgrade. All host significant populations of Russians who fled the country following Moscow's military offensive on Ukraine.
