Thousands of Russian opposition activists are marching through Moscow decrying President Vladimir Putin's authoritarian rule and calling for the release of people they consider political prisoners.

Wednesday's march is in support of 27 people who face charges related to a protest that turned violent on the eve of Putin's inauguration more than a year ago.

Sixteen of the defendants have remained in jail pending trial on charges that could send them to prison for up to 10 years.

Opposition leader Alexei Navalny and his wife are leading the marchers behind an orange banner saying: "For your freedom and ours."

Navalny is on trial in a separate case in which he is accused of embezzlement. He claims the charges are punishment for his exposure of high-level corruption.