Disseminating information about the war that the authorities consider to be false has been a crime since Friday that could result in up to 15 years in prison in Russia.
Despite this, protests against the war in Ukraine have continued over the weekend.
On Sunday, more than 3,500 people were arrested during demonstrations around Russia, according to the state-controlled Russian media company TASS.
Demonstrations across the country
“No to the war!
You should be ashamed of yourself! ”
shouts a young man in the city of Khabarovsk in eastern Russia before being abducted by police.
Several protesters raise signs with anti-war messages to cameras before being arrested in a square in Moscow.
A total of almost 900 people were arrested during protests in the capital on Sunday and the number is expected to rise, according to the human rights organization OVD.
Navalny calls for protests
Earlier this week, the imprisoned Russian opposition politician and activist Alexei Navalny called on people around the world to demonstrate against the war on Sunday.
Demonstrations against the Russian invasion of Ukraine have been going on since Putin ordered Russian forces to enter Ukraine on February 24.
Since then, more than 10,000 people have been arrested in protests around Russia.