MOSCOW  - Thousands of opposition activists took to their cars Sunday to protest Prime Minister Vladimir Putin’s bid to return to the presidency, in a rally held on a Moscow ring road.

Some 3,000 cars joined the protest, according to organisers: police said they numbered only 300. With horns blaring, they drove for some three hours, causing major bottlenecks on the 15-kilometre (nine-mile) ring road — known as the Garden Ring — encircling city centre.

Some cars were papered over so they were entirely white — the colour of the anti-Putin movement — others were decked with white ribbons and balloons, and some sported snowmen on their roofs in the action dubbed “white ring”.

The operation was organised via social networking Internet sites by the Voters League, set up by journalists, bloggers, writers and artists ahead of the March 4 presidential poll to campaign for democratic elections. Many passers-by including several elderly people, waved white handkerchiefs at the protesters. “Today is an example of people who ... have come out in the streets of the city to show that we are numerous, that we are afraid of nothing,” said protester Lada Stupishina, 43.

“We want the party of thieves and swindlers that Putin leads to go away,” she added, using opposition figure, blogger Alexei Navalny’s description of Putin’s United Russia party, which is tipped to win the elections.

Navalny also took part in the protest. “Our aim was to encircle the ring road, which is what we have done using two lanes,” he told AFP. “There were a great number of passers-by who approved our action,” he added.

“They got pleasure from it, it seems to me. We have taken another civic step and we had fun.”

Organisers hope to attract at least 50,000 people to a protest in the centre of Moscow next Saturday. Protests in December against the conduct of parliamentary elections drew tens of thousands of people, indicating growing discontent with Putin’s rule.

The protest movement has dented Putin’s once all-conquering popularity, but the Russian strongman is still expected to win the presidential polls in the absence of strong challengers.

Putin is standing for a third Kremlin term after his four-year stint as prime minister, in defiance of opposition warnings he has been in power too long.

Russia’s election commission on Friday barred the only liberal contender, Grigory Yavlinsky in a decision bitterly denounced by opposition activists, and which Washington described as disappointing.

On Saturday, the Soviet Union’s last leader Mikhail Gorbachev called for a referendum in Russia on constitutional reform to end the “autocracy” he said had emerged under its current political system.

He has also called for Putin to quit politics and for fresh polls to replace the parliament elected in the disputed December 4 legislative elections that sparked the protests.