Russia?s election authorities yesterday barred former prime minister Mikhail Kasyanov, a sharp critic of the Kremlin, from running in a March presidential election against President Vladimir Putin?s chosen candidate.

Kasyanov?s supporters said the March 2 poll would now be a farce and the move showed the Kremlin feared any real challenge to Dmitry Medvedev, the man Putin has backed to succeed him.

The Election Commission voted unanimously to refuse to register Kasyanov because of technical errors, including forgery, which it said were found in some of the 2 million signatures needed to register him as a candidate.

?This means the elections will be a farce,? Kasyanov?s spokeswoman, Yelena Dikun, said by telephone. ?It shows the authorities are afraid of any competition, it means the authorities fear any alternative points of view,? she said. ?They are afraid, just so afraid.?

Kasyanov, 50, who served as Putin?s first prime minister, has accused his former boss of rolling back democracy, mismanaging Russia?s booming economy and creating a political system that is dangerously dependent on one man. But he had little chance of winning an election, with opinion polls showing he had less than 1 percent support.

But blocking Kasyanov from the race may raise concerns about the fairness of the vote, which the opposition says is slanted in favor of Medvedev, a 42-year-old first deputy prime minister who polls forecast will win a landslide in the election.

The election will be closely monitored by the United States and the European Union after international observers said last year?s parliamentary vote was skewed by interference from the authorities. Putin,55, who is unable to seek a third successive term under constitutional limits, has endorsed Medvedev and is expected to remain influential after the election.

The Election Commission said problems were found with 13.36 percent of the 2 million signatures Kasyanov submitted to be registered. Rules allow just 5 percent of signatures to be invalid. ?What we did with Kasyanov is following the rules of the Russian Federation to ensure the proper registration of candidates,? Nikolai Konkin, secretary of Russia?s Central Election Commission, told reporters.

Konkin said the move meant four candidates would take part in the presidential election: Medvedev, Communist Party leader Gennady Zyuganov, firebrand nationalist Vladimir Zhirinovksy and Democratic Party leader Andrei Bogdanov. Kasyanov, formerly a suave career bureaucrat who served as prime minister for the first four years of Putin?s rule, turned on his former boss after being sacked in 2004.

Conor SWEENEY