Exiled Russian tycoon Boris Berezovsky on Monday called the Kremlin and Russia's chief prosecutor "seriously sick" for blaming the murder of journalist Anna Politkovskaya on foreign elements.
"They are really mad: [Russian Prosecutor General Yury] Chaika, the Kremlin, the prosecutor's office, they're seriously, seriously sick," London-based Berezovsky said.
Instead, he said, the Kremlin was behind the murder of Politkovskaya last October, and also that of former Russian agent Alexander Litvinenko in London last year.
"Scotland Yard, they know who is behind Litvinenko's murder," Berezovsky said. "Mr Lugovoi is a former KGB guy and it's organized by FSB [the successor of the KGB]."
"I don't have any doubt that the murder of Politkovskaya is the same case," he said. "It means the Kremlin is behind that."
He also said that he was "not absolutely surprised" by Chaika's announcements earlier on Monday.
Russia on Monday announced 10 arrests in the killing of Politkovskaya, blaming her murder as well as other high-profile killings on a foreign-based campaign to oust President Vladimir Putin.
Chaika told Putin in a televised meeting that police had made "serious progress."
"To date we have arrested 10 people. In the very near future they will be charged with committing this serious crime," he said in the comments, which were shown on NTV.
He appeared to point the finger at exiled Putin critics, saying those behind the killing -- which highlighted dangers faced by journalists in Russia and badly embarrassed the Kremlin -- were abroad.
"The individuals interested in eliminating Politkovskaya can only be ones living beyond Russia's borders," Chaika later told reporters. "It's useful above all to people and structures that are aimed at destabilizing the country and undoing the constitutional order in Russia."
Chaika said the same group of killers may have been behind the 2004 murder of another journalist, US citizen Paul Klebnikov, and the murder in Moscow last year of the central bank's deputy chief.
"As our probe shows, the string of murders that took place were the same type of provocation," Chaika said.
"It's not a first attempt. There is a list of previous murders that were similar provocations," he said.
According to Chaika, the actual killers included serving and retired members of Russia's interior ministry and elite federal security service. They were led by someone from war-torn Chechnya, he said.
However, the motivation was "aimed at provoking external pressure on our country's leadership," Chaika said.
Chaika's comments appeared to refer especially to Berezovsky, who has political asylum in Britain, and has repeatedly called for Putin to be forced from office.
An extradition request would be issued for the alleged mastermind "when we have fuller proof," Chaika said.
Politkovskaya was a journalist for the independent twice-weekly Novaya Gazeta. She had been almost alone in the Russian media in probing war crimes in Chechnya. She also wrote a series of books critical of Putin's rule.
The most powerful media organizations are all under state control in Russia and criticism of the Kremlin is rare.
Oleg Panfilov, director of the Moscow-based Center for Journalism in Extreme Situations, said the announced progress in the Politkovskaya case did not signal any improvement in reporters' safety.