Putin: Demands Of and Threats Against

Marina Litvinenko, widow of Alexander Litvinenko, is seeking a ruling from the European Court of Human Rights that the Russian state was complicit in poisoning the former security agent with radioactive polonium.

Louise Christian, Litvinenko’s lawyer claimed she had obtained expert evidence that the polonium had come from Russia's Avangard plant, a state facility surrounded by tight security.

The former KGB security officer became a Kremlin critic in exile, and was poisoned by polonium slipped to him in a cup of tea. He spent three weeks dying in agony in London.

Britain wants to prosecute another ex-KGB man, Andrei Lugovoi, for the murder. Russia strongly denies state involvement in the killing and refuses to hand over Lugovoi because its constitution bars it from extraditing its own nationals.

Exiled Russian businessman Boris Berezovskii, a friend of Litvinenko and Kremlin opponent whom Russia has tried unsuccessfully to extradite from Britain has stated that he believes British authorities know the source of the polonium.

Berezovskii said Putin had violated the constitution and therefore his ouster was legitimate and forecasts a possible uprising like Ukraine's Orange Revolution between elections in December and March.

He said such an uprising could come after parliamentary elections on December 2 and before presidential polls three months later.

Democratic movements staged the Orange Revolution in the former Soviet republic of Ukraine in 2004, a popular uprising that brought pro-Western President Viktor Yushchenko to power.

Berezovskii, who faces a number of charges in Russia, was a key Kremlin insider in the 1990s, but left Russia after coming into conflict with Putin and was granted political asylum in Britain in 2003.