Russia's main opposition leader, Alexei Navalny, has been arrestedat an anti-corruption protest he organised in the capital, Moscow.
Thousands of people have joined rallies nationwide, calling for the resignation of Prime Minister Dmitry Medvedev over corruption allegations.
Most of the marches were illegal, organised without official permission.
Police have been deployed in large numbers, and dozens of other protesters have been detained across the country.
Source BBC News.