LONDON - British scientists probing the death of Alexander Litvinenko said today that two more people had been contaminated with the same radioactive poison that killed the former Russian spy.
The growing number of cases raised fears of wider contamination in Britain, where Litvinenko's accusation that he was poisoned by Moscow has already strained relations with Russia.
Mario Scaramella, an Italian contact of Litvinenko, was admitted to hospital in London after polonium 210 was detected in his body, but a medical spokesman said he was "currently well and shows no symptoms of radiation poisoning".
Officials said an adult female relative of Litvinenko had shown traces in her urine of polonium 210, the same isotope that poisoned the former agent and outspoken Kremlin critic.
But they said she was not in short-term danger and any long-term risk was likely to be very small.
"It is a fraction of the lethal dose that Mr Litvinenko himself had," Home Secretary John Reid said.
The British government has struggled to allay public health concerns over radiation and police remain silent about their investigation into Litvinenko's slow and agonising death.
The case has sparked a variety of theories, many centring on the possible involvement of rogue Russian agents.
Scaramella met Litvinenko at a London sushi restaurant on November 1, the same day the Russian fell ill.
Litvinenko, who also met two Russians in a London hotel on the same day, believed President Vladimir Putin had ordered him killed. Russia has dismissed the charge as ridiculous, but the case has created diplomatic tension between London and Moscow.
Authorities say polonium is not dangerous unless swallowed, inhaled or absorbed through a wound.
But public concern has mounted as authorities have revealed that traces of radiation have been found at 12 sites and aboard planes which have carried more than 33,000 passengers in the past month, many flying between London and Moscow.
Italian Senator Paolo Guzzanti told Reuters after speaking to Scaramella's lawyer: "Mr. Scaramella himself is in hospital and he is very depressed ... The level (of radiation) in his urine is very, very low apparently but still worrying his doctors."
Scaramella, who describes himself as a security consultant, said last week he had met Litvinenko on Nov. 1 to show him emails from a mutual source warning both their lives might be in danger. He said Litvinenko had told him not to worry.
A British government source said London had contacted the Italian health and foreign ministries, and the Italians may also decide to check levels of radiation on aircraft.
Italy's Health Ministry said it was in contact with British authorities and added in a statement: "It is underlined that at present there is no reason to hypothesise dangers of any type to public health."
A spokesman for Easyjet said Scaramella had flown with it from Naples to London on October 31 and back again on November 3. The airline was in contact with the Health Protection Agency and would take any necessary steps.
Earlier today, three pathologists wearing protective suits to guard against radiation carried out a post-mortem on Litvinenko at the Royal London Hospital.
British media reported that scientists at the country's Atomic Weapons Establishment (AWE) had traced the source of the polonium to a nuclear power plant in Russia.
The head of Russia's state atomic energy agency Rosatom, Sergei Kiriyenko, told the government newspaper Rossiiskaya Gazeta Russia produces only 8 grams of polonium 210 a month. He said production was under tight government control.
In a separate development, Irish health authorities said they were checking for radiation at a Dublin hospital where former Russian prime minister Yegor Gaidar was treated after collapsing at a conference last week.
British police said they saw no link between the Litvinenko case and that of Gaidar, who was struck down by a mystery illness that has so far baffled doctors.