Alexander Litvinenko died November 23, 2006 after being poisoned with the radioactive substance Polonium-210. In December, a Scotland Yard team arrived in Moscow to question two key suspects in the case, spies-turned-businessmen Andrei Lugovoy and Dmitri Kovtun.
Berezovsky pledged to comment on the questioning, which took place in the afternoon in the presence of Scotland Yard officials, later.
Earlier this year, Scotland Yard handed the Litvinenko case over to Britain's Crown Prosecution Service, and the Russian Prosecutor's Office launched an inquiry of its own.
Berezovsky was granted political asylum in the U.K. after fleeing Russia, where he is wanted on fraud charges. The Russian Prosecutor's Office has repeatedly approached British authorities with a request that the tycoon be extradited to his country of origin, but each request has been denied.
Litvinenko was charged with abuse of office in Russia in the late 1990s after he publicly claimed he had been ordered by his superiors at the Federal Security Service (FSB) to assassinate Berezovsky.
He met the oligarch through a friend, Alex Goldfarb, on his arrival in the U.K. several years later, and began working for him as an adviser.
