Billionaire Mikhail Prokhorov said Monday he is running for president of Russia, taking on Prime Minister Vladimir Putin in next year's election.
Prokhorov, who owns the New Jersey Nets basketball team, made the announcement at a news conference in Moscow.
"I made probably the most serious decision in my life," he said. "I am running for president."
RIA Novosti, Russia's state news agency, said Prokhorov plans to look for support within Russia's middle class.
Prokhorov in September gave up his bid to lead the Just Cause party in the parliamentary poll. He allegedly was dismissed as leader of the party for not following the Kremlin line, RIA Novosti reported.
"These past 2 1/2 months, my colleagues and I have been quietly and calmly working to build an infrastructure that will allow us to gather 2 million signatures," The Wall Street Journal quoted Prokhorov as saying.
He needs the signatures to face Putin, who is looking to return to the office he held from 2000-2008, and other presidential candidates from parties with parliamentary representation to succeed President Dmitry Medvedev, who is not seeking re-election. The field of candidates also includes Communist Party chief Gennady Zyuganov.