Russia elections: Officials bar liberal Yavlinsky
Russias electoral commission has barred the liberal opposition leader Grigory Yavlinsky from running in the March presidential election.
Officials reported irregularities in more than a quarter of the signatures collected in support of Mr Yavlinsky.
Independent candidates, whose parties failed to get into parliament, have to collect two million signatures to take part in the 4 March poll.
Prime Minister Vladimir Putin is widely expected to become president again.
Officials check at least 400, 000 signatures presented for each candidate and if more than 5% are found to be irregular the candidate is disqualified.
Billionaire businessman Mikhail Prokhorov, another independent candidate, called the disqualification of Mr Yavlinsky "a blow to the legitimacy of the elections".
Mr Yavlinsky, 59, was not considered a major rival to Mr Putin, who is seeking a third term as president.
Mr Yavlinsky insisted that "all the signatures are authentic".
His leadership of the Yabloko party dates back to the 1990s when he challenged Boris Yeltsin for the presidency. But recent opinion polls have put his support at under 5%.
Claims of vote-rigging in the December parliamentary vote sparked protests across Russia against Mr Putin and his United Russia party.
The governor of Irkutsk region in Siberia, Dmitry Mezentsev, was also barred from running in the presidential election on Friday.
So far the officials have approved the candidatures of Mr Putin, Communist Party leader Gennady Zyuganov, nationalist Liberal Democrat Party leader Vladimir Zhirinovsky, Sergei Mironov of A Just Russia and Mr Prokhorov.