Sunday's parliamentary elections in Russia were unfair and should be annulled, former Soviet leader Mikhail Gorbachev has said.
Speaking to the Interfax news agency on Wednesday, Gorbachev said Russian authorities should admit "there were numerous falsifications and rigging" and that the results did not reflect the people's will.
"More and more people are starting to believe that the election results are not fair," he said. "I believe that ignoring public opinion discredits the authorities and destabilises the situation."
Gorbachev added: "I think they can only take one decision - annul the results of the election and hold a new one."
His comments come amid the mass arrests of protesters demonstrating against the rule of prime minister Vladimir Putin. The protests are the largest Russia has seen for years.
The Organisation for Security and Co-operation in Europe (OSCE) said the election was slanted in favour of Putin's United Russia party and reported incidents of ballot box stuffing.
Despite suspected fraud, support for United Russia slumped to just under 50% of the vote.
According to the BBC least 800 protesters are said to have been arrested in a nationwide crack down by police. While almost 14,000 Russians have indicated on Facebook that they intend to join a demonstration in Moscow on Saturday.