Updated

Boris Berezovsky, the exiled Russian tycoon who has emerged as one of the Kremlin's most vocal opponents, called Friday for the use of force to oust President Vladimir Putin and claimed he has support from some in the country's political elite.

In response, Russian authorities angrily urged Britain to strip Berezovsky of his political asylum and extradite him to Russia.

Russia's chief prosecutor said he ordered a new criminal investigation opened over Berezovsky's remarks, which appeared aimed at rattling the Kremlin and fomenting political unrest ahead of crucial elections.

Berezovsky said the Russian leadership could only be replaced by force and that he was in contact with Kremlin insiders who supported his vision for change.

"Putin has created an authoritarian regime against the Russian constitution," Berezovsky told The Associated Press by telephone in Britain. He added, "I don't know how it will happen, but authoritarian regimes only collapse by force."

Britain's Foreign Office said it was monitoring Berezovsky's comments.

"We deplore any calls for violent overthrow of any sovereign state. We expect everyone living, working or visiting the U.K. whatever their status to obey our laws," said a Foreign Office spokeswoman, speaking on condition of anonymity in line with department policy.

Berezovsky later issued a statement to "clarify" his words, saying he did not "advocate or support violence." He did, however, say that under Putin's government "elections are not a viable means of ensuring democratic change in Russia."

Russian officials responded that that Berezovsky was abusing his asylum status and stressing that Britain must now reconsider its previous refusal to hand him over for prosecution.

"I think London has lots of good lawyers who know perfectly well that calls for the forceful overthrow of the constitutional regime in a foreign country are enough grounds for proper legal measures," Foreign Minister Sergey Lavrov said.

When Berezovsky was pressed about what he meant by "force," he said he wanted to institute change by using "force like in Ukraine or Georgia." In those two former Soviet republics, opposition leaders won power after nonviolent street demonstrations.

Police on Friday promised a harsh response to plans by anti-government protesters to march through Moscow's center on Saturday — the first of two weekend demonstrations in Russia's largest cities.

Garry Kasparov, a former world chess champion who is another vociferous Kremlin critic, said march organizers had rejected a proposal by city authorities to gather in a single location for a meeting, rather than marching down one of Moscow's main avenues.

He said the marches would highlight what the government's authoritarian policies and the growing disparity between Russia's rich and poor. The march, Kasparov said, "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."

Berezovsky told AP he was in close contact with close associates of Putin, and had offered funding and technical support to achieve change. But he would not reveal precise details of his activities, saying "it would destroy what I'm doing."

Neither would Berezovsky reveal the identities of his associates in Russia because, he said, "they will be killed like Alexander Litvinenko." Litvinenko, a former KGB officer and friend of Berezovsky, died in a London hospital in November after being poisoned by radioactive polonium-210. On his deathbed, he blamed the Kremlin for his poisoning — claims the government has denied.

In the past, Berezovsky has talked about providing money to opposition forces rather than government insiders.

Russian Prosecutor General Yuri Chaika said he had ordered a new criminal case opened against Berezovsky because his comments amounted to "calls for the violent seizure of power," Russian news agencies reported. The spokeswoman for Chaika's office, Marina Gridneva, said prosecutors would once again officially appeal to Britain to hand Berezovsky over, stripping him of his asylum.

A former Kremlin insider, Berezovsky fell out with Putin and fled to Britain, which granted him refugee status in 2003 — turning down an earlier Russian extradition request. Russian prosecutors made a renewed effort following similar comments last year, but a British judge ruled that he could not be extradited because his asylum status meant he was protected by the Geneva Conventions.

Berezovsky's latest remarks come amid rising tensions ahead of Russia's parliamentary elections in December and a presidential vote next March. Putin is barred by the constitution from seeking a third consecutive term.

Critics say Putin has rolled back democracy and consolidated power in the Kremlin, in an effort to ensure the current leadership retains power following the presidential election.

Berezovsky — who once controlled an oil, automobiles and media empire here — gained a reputation for ruthlessness in the 1990s when he became one of Russia's wealthiest tycoons in the chaotic and often violent post-Soviet period.