Former Soviet President Mikhail Gorbachev has said Sunday’s Russian parliamentary election was marred by fraud and has called for a re-run.
“The country’s leaders must admit there were numerous falsifications and rigging and the results do not reflect the people’s will,” he said.
Protesters have called for new rallies as arrests in Tuesday’s crackdown in Moscow and elsewhere reached 800.
Key figures in the protest movement are starting 15-day jail sentences.
State TV channels have ignored the protests, giving coverage only to rallies in support of the government.