Moscow ? A key witness in the radiation death of former Russian intelligence officer Alexander Litvinenko denied involvement in the poisoning Friday, saying he is being unjustly accused in the media.

Andrei Lugovoi, who met Litvinenko in London hours before the ex-KGB agent fell ill, would not discuss details of the investigation or offer a theory of the poisoning, citing a pledge to investigators. But he said he was not to blame.

“I am not regarded as a suspect, I am regarded as a witness,” Lugovoi told the Associated Press in a telephone interview. “Police are not accusing me of anything. As for all that is being said – it’s nothing but hysteria in the media.”

Lugovoi said he was undergoing tests at a Moscow clinic. Media reports have said Lugovoi was being checked for radiation.