Thousands of cars flying white ribbons and white balloons have circled central Moscow in a protest against Russian Prime Minister Vladimir Putin.

The cars jammed the inner lanes all along the 10-mile Garden Ring, which has as many as 16 lanes of traffic at its widest points.

More protesters stood along the side of the road waving white ribbons and flags as the cars passed, their horns blaring.

White ribbons became an opposition symbol during demonstrations to protest against alleged fraud in a December 4 parliamentary election said to have boosted the results for Mr Putin's party.

Tens of thousands turned out for two mass protests last month to demand free and fair elections, and protest organisers are now preparing for a third big demonstration.

Mr Putin is running in a March 4 presidential election to reclaim the post he held from 2000 to 2008. He is expected to win, but is under pressure to show he can win fairly.