MOSCOW -- The Kremlin and some of its most determined critics prepared to face off on the streets of Moscow and St. Petersburg in what could be a key test of the Russian opposition's determination before parliamentary and presidential elections.
As thousands of police stood ready in Moscow to thwart today's Dissenters' March against President Vladimir Putin's government, exiled Russian billionaire Boris Berezovsky added to tensions by saying only force could bring down the "authoritarian regime."
If the protest in Moscow and a similar one in St. Petersburg tomorrow draw large crowds, they could give momentum to Russia's beleaguered opposition and spur a long season of demonstrations against the government, which critics say has rolled back democracy.
If they flounder, it could signal further irrelevancy for the opposition -- fractured by infighting and marginalized by Putin's popularity and Kremlin maneuvering -- as the country moves toward parliamentary elections in December and next year's critical presidential vote.
In response to Berezovsky's call for the ouster of Putin, Russia's chief prosecutor opened a criminal case against him on charges of plotting a coup. Prosecutor General Yuri Chaika said the remarks "contained an open call to overthrow the constitutional order of Russia."
Russian officials also said they would ask British authorities to strip Berezovsky of asylum and to extradite him to Russia. London's Metropolitan police began an investigation into whether Berezovsky's comments, first published in yesterday's Guardian newspaper, violated any British laws.
Berezovsky, a former Kremlin insider, sought political asylum in Britain three years ago and now lives in London. He has been a persistent thorn in Moscow's side.
Since Putin took office in 2000, the Kremlin has moved to centralize power in Russia, created an obedient parliament, abolished direct gubernatorial elections and tightened restrictions on civic groups. Kremlin critics are now rarely heard on major television networks.
But Putin has brought stability to the country after a decade of chaos and has presided over rapid economic growth, helped by high oil prices. Polls rate him by far the most popular political figure in Russia.
The United States has accused Putin's government of quashing independent voices while Russia blasts Washington for meddling in its internal affairs and in its historic sphere of influence.
Russia will hold parliamentary elections in December and a presidential vote next March. Putin is barred by the constitution from seeking a third consecutive term.
The weekend protests would be the latest in a series of antigovernment demonstrations. Previous protests were dispersed by riot police or broken up by mass arrests. Moscow authorities have barred protesters from marching down a major thoroughfare but proposed they could meet a single location.
Garry Kasparov, a former world chess champion and vociferous Kremlin critic, said protesters will denounce Putin's policy of consolidating political power as well as the growing disparity between rich and poor in Russia.
"The Dissenters' March will clearly show that all this stability -- which the Kremlin-controlled television stations trumpets, which is the bait that unfortunately the Western media have swallowed -- is an illusion, an illusion that will disappear when it collides with reality," Kasparov said Thursday.
"The street is the only place where the people can really express their views," he said.
More than 9,000 police and Interior Ministry officers will be on Moscow streets, a senior city police official said. Metal barricades were erected on the central square where the march is set to begin.