MOSCOW, December 6 (RIA Novosti) - Investigators might not be able to question Wednesday a key Russian witness in the case of an ex-FSB agent's death in London, as he is undergoing a medical examination, a source close to the witness said.
Andrei Lugovoi, a businessman and former security service officer, earlier said he was willing to meet with Scotland Yard detectives, currently in Moscow investigating the murder of his fellow security officer Alexander Litvinenko.
"An interview has been scheduled for today, but Lugovoi is still undergoing medical checks, and he has not been questioned so far," the source said, adding that the questioning could be postponed until Thursday.
U.S. TV channel ABC News said Wednesday, citing an unidentified British official, that investigators were treating Lugovoi as the main suspect in the November 23 death by radiation poisoning of Litvinenko, who defected from Russia in 2000 and was known as an outspoken Kremlin opponent.
Lugovoi's lawyer, Andrei Romashov, said his client would be questioned only as a witness, possibly December 7 or 8.
"The British Embassy has told us [the defense team], and Scotland Yard experts have informed Lugovoi, that he will only be questioned as a witness," he said, adding that doctors had allowed Lugovoi to be questioned.
"He is undergoing examination in the hospital in the wake of recent events. He is worried for his life," Romashov said.
He also said Lugovoi's business partner, Dmitry Kovtun who also met with Litvinenko on the day he fell ill, had been questioned Tuesday. "And the questioning is continuing today," he said.
Lugovoi told The Times and The Daily Telegraph last week that he and two of his business partners met with Litvinenko in London November 1, the day the former security officer, a British national, is believed to have received a fatal dose of radioactive polonium-210.
Traces of radiation have been detected in the hotel rooms in London where Lugovoi stayed in October and November, and on the airliners in which he flew to the UK, the popular Russian daily Kommersant said Wednesday.
ABC also claimed Russian authorities have hindered British investigators' efforts in Moscow.
Russia's top prosecutor said Tuesday Lugovoi might be questioned if doctors give their permission. But Yury Chaika said Scotland Yard detectives will not be allowed to arrest and extradite Russian suspects who may emerge in the case, as it would contradict the Russian Constitution.
He also said any interviews of suspects in Scotland Yard's investigation will be carried out by Russian prosecutors.
