Businessman Andrei Lugovoi, an ex-KGB agent, was one of the last contacts to have met with Litvinenko before the latter was hospitalized with symptoms of poisoning in November. A lethal dose of radioactive polonium-210 was found in his body after his death.
Lugovoi, who is currently being tested for radiation poisoning at a Moscow hospital, may be questioned later in the day by Scotland Yard detectives, who came to the Russian capital a week ago for their probe into the Litvinenko case.
Last Wednesday, Russian and British investigators spoke with Dmitri Kovtun, a business partner of Lugovoi, who also met with Litvinenko in London shortly before his death.
Western media have suggested the Po-210 used to poison Litvinenko might have been produced in the hotel room where Lugovoi stayed on a recent visit to London.
The potential suspect has consistently denied any involvement in the poisoning of the defector, and has expressed his willingness to cooperate with investigators.
