Kasyanov in December 2005 failed in his attempt to take over the helm of the opposition Democratic Party of Russia.
He says his new movement, which has yet to be named, will strive to alter the country's political balance ahead of the 2008 presidential election.
Kasyanov was fired by President Vladimir Putin in 2004. He has emerged as a harsh critic of the Russian leader.
RFE/RL Russia Report
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