Andrei Lugovoy has damage to vital organs consistent with exposure to dangerous levels of radiation, Interfax news agency reported.
"Today I spent the whole day undergoing necessary medical procedures," he added.
Dmitry Kovtun, Lugovoy's business partner, is also in hospital with suspected radiation poisoning.
Mario Scaramella, an Italian contact of Litvinenko, has undergone treatment in
Interfax said its information on Lugovoy's condition came from his medical notes. "Disruption in the functioning of some organs affected by radiation nuclides has been found (in Lugovoy)," it quoted a source as saying.
Meanwhile, police in
The statement did not say when Kovtun was last in
Lugovoy and Kovtun met Litvinenko at
He has denied any part in Litvinenko's poisoning and offered to help police.
British detectives continue to work in