A leading Russian opposition group has launched a Web site to document what it described as government persecution of political activists, human rights campaigners and independent journalists.

The Other Russia group, headed by former chess champion and rights activist Garry Kasparov said its "Chronicle of Persecutions" will provide information about government repression of activists who have faced increasing persecution in the past year.

Earlier Wednesday, former deputy prime minister Boris Nemtsov announced his withdrawal as a candidate in Russia's March presidential elections.

Mr. Nemtsov, a leader of the Union of Right Forces party Wednesday, urged the democratic opposition to back a single candidate in the vote. He also called the upcoming presidential election a farce and accused the Kremlin of using propaganda, security and bureaucratic pressures against the opposition. Nemtsov then suggested that other candidates also withdraw unless the Kremlin fails to halt such practices.

Russian President Vladimir Putin has openly backed United Russia Party nominee Deputy Prime Minister Dmitri Medvedev in the race.

Other presidential candidates are former Russian Prime Minister Mikhail Kasyanov, Communist Party leader Gennady Zyuganov, Liberal Democrat Vladimir Zhirinovsky and Andrei Bogdanov of the Democratic Party.

Russia's constitution bars Mr. Putin from seeking a third consecutive term.

Some information for this report was provided by AFP, AP and Reuters.