More than 2,000 anti-war protesters were detained in different Russian cities on Sunday, said OVD-info, an NGO that monitors arrests at the protests.
Since President Vladimir Putin ordered the invasion of Ukraine More than 5,200 pacifist demonstrators have been arrested, added that NGO.
AFP reporters witnessed the arrest of some 200 people in Saint Petersburg, Russia’s second largest city, on Sunday.
Thousands have defied Russia’s strict laws on demonstrations of protest to organize them.
About 400 people had gathered in the old imperial capital and many carried signs with legends such as “No to war”, “Russians go home” and “Peace for Ukraine”.
“It’s a shame there are hundreds, maybe thousands of us and not millions,” engineer Vladimir Vilokhonov, 35, who took part in the protest, told AFP.
“I am against the war. I was born in 1941 and I know what it means,” said Valeria Andreyeva, born the year Nazi Germany attacked the Soviet Union.
In Moscow, AFP reporters saw the arrest of some 50 people in Pushkin Square.