Russian opposition figure Sobol attends a rally to demand free elections in Moscow

Moscow - Supporters of the Russian political opposition conducted an unsanctioned protest march through central Moscow on Saturday, a week before controversial elections.

The rally was the latest in a wave of weekend protests that erupted last month after several opposition candidates were rejected from the ballot for the September 8 city council elections.

More than 2,000 people have been detained at the protests. Police have come under fire for their heavy-handed approach to the demonstrations.

Saturday's demonstration began with a remarkably light police presence. 

"Russia will be free," protesters chanted as they marched through Moscow's Boulevard Ring, a main thoroughfare across the city centre.

Russia's top investigative agency had warned against attending unsanctioned protests this week, saying: "A few hundred likes under a photo and a couple minutes of glory on social networks is the price for a destroyed life."

Saturday's protest was organized by the team surrounding opposition politician Alexei Navalny, who was released from jail last week after serving a 30-day sentence for breaking a law against holding unsanctioned protests.

Mayor Sergei Sobyanin had "taken away Muscovites' right to fair elections," Navalny's team said on Facebook.

"Independent candidates have been placed under arrest. Peaceful protesters are implicated in criminal cases," they wrote.

About 1,500 people openly indicated that they would attend the protest.

Navalny is not currently running for office. He ran for mayor of Moscow six years ago, garnering a quarter of the vote according to official figures.

Sobyanin, endorsed by the ruling political party, won a razor-thin majority at 51 per cent in that election. Navalny's supporters accused the electoral authorities of vote-rigging.