Police have arrested as many as 300 people, including journalists, as demonstrators in Moscow defied a ban on unapproved protests.
This is the second day people have taken to the streets, angry at alleged election fraud on Sunday, and fed up with Vladimir Putin’s United Russia Party.
More people were held after similar protests in St Petersburg and the southern city of Rostov-on-Don.
Among those detained by police are opposition politician Boris Nemtsov, prominent activist Ilya Yashin and opposition blogger Alexei Navalny.
Nemtsov, a liberal politician and former deputy prime minister, is now a critic of the government.
After being arrested on Monday, blogger Alexei Navalny and activist Ilya Yashin both appeared in court on Tuesday, and have each been sentenced to 15 days in prison after being convicted of offences including obstructing the course of justice.
President Dmitry Medvedev has spoken out, after criticisms from Washington and suggestions from US Secretary of State Hilary Clinton that Sunday’s ballot was neither free nor fair.
“If international organisations say they observe violations that is one thing, but the issue of Russia’s political system is not their business. Soon they’ll be telling us how we should write our Constitution,” Medvedev told the Head of the Central Electoral Commission Vladimir Churov.
Despite election results marking a big fall in support for Prime Minister Putin’s United Russia Party just months before he makes another bid for the presidency, his supporters organised their own rallies on Tuesday.