Russian president Vladimir Putin has won a fourth term in office with nearly 77% of the vote - his highest ever score - giving him a mandate to pursue his nationalist policies for another six years.

Thousands of opposition supporters gathered today outside the old KGB headquarters in central Moscow today to mark a year of mass protests against Vladimir Putin and his government.

Tens of thousands of Russians flooded Moscow's tree-lined boulevards today in the first massive protest against president Vladimir Putin's rule since his inauguration in May - a rally that came even as police interrogated key opposition leaders.

Russian police searched the homes of prominent opponents of President Vladimir Putin in a clear warning he is losing patience with dissenters before a major rally today that could draw tens of thousands of people challenging his rule.

Russian investigators searched the apartments of several opposition leaders today and called them in for questioning, raising tensions on the eve of a large protest against President Vladimir Putin.