10 People Showing Signs of Polonium-210

Exiled Russian oil baron Leonid Nevzlin pauses during an interview in his house in the coastal city of Herzeliya near Tel Aviv in this photo taken Monday, May 2, 2005. The Russian Prosecutor General's office said Wednesday that it was investigating the possible role of the former top owner in the Yukos oil company in the poisoning death of ex-Russian spy Alexander Litvinenko. The prosecutor's office said in a statement that Nevzlin, who is living in exile in Israel, and other Yukos figures wanted by Russia, could have ordered Litvinenko's murder in London last month. It did not give any details of the allegations against Nevzlin. (AP Photo/Ariel Schalit, File) (Ariel Schalit - AP)

LONDON -- Ten people have shown signs of low-level exposure to polonium-210, the rare radioactive element that killed one-time Russian intelligence agent Alexander Litvinenko, British health authorities said Thursday.

The Health Protection Agency said those affected had not suffered enough exposure to cause illness in the short term, and the long-term risk was also very small.

Seven of those who tested positive were staff from the Pine Bar in London's Millennium Hotel, which Litvinenko visited on Nov. 1, the day he became ill, the authority said.

Litvinenko, a Kremlin critic who lived in London, died of poisoning from radioactive polonium-210 in a London hospital on Nov. 23. In a deathbed statement, he accused Russian President Vladimir Putin of ordering his murder, allegations which the Kremlin has dismissed.

British police say they are treating his death as murder and have conducted investigations in both London and Moscow. Around a dozen London sites have been tested for traces of the rare polonium-210.

A spokeswoman for the Health Protection Agency said 3,837 people had called health authorities with concerns that they may have been contaminated. A total of 670 cases had been followed up and 486 urine samples tested.

However, the risk to the general public from polonium-210 was "likely to be very low," said the spokeswoman, speaking on condition of anonymity in line with authority policy.