British news reports say an Italian academic and eight other people are undergoing tests for exposure to polonium 210, the radioactive element found in the body of a former Russian spy who died last week.
The academic, Mario Scaramella, is reported to be under British police protection. He met with former spy Alexander Litvinenko on November 1 at a London sushi restaurant. Litvinenko told investigators he was poisoned there. Before he died, Litvinenko accused Russian President Vladimir Putin of ordering his death.
Britain's Health Protection Agency selected the eight others from more than one thousand people who called a hotline with concerns they may have been exposed to polonium.
In other news, authorities say they are testing two more central London locations for polonium traces.
On Tuesday, British Prime Minister Tony Blair told reporters that "no political barrier" will hinder the investigation into Litvinenko's death.
Mr. Blair said he will speak to President Putin about the case at the appropriate time.
Police have already sealed off six locations with traces of polonium, including the London office of exiled Russian billionaire Boris Berezovsky, a friend of the dead spy, and the sushi restaurant.
Litvinenko died in the hospital Thursday after claiming he was poisoned for his opposition to President Putin. The Kremlin has denied any link to the case. Russia's Prosecutor General's office said Tuesday that it is ready to help Scotland Yard investigate the case. But the office said it has not received a British request for help.
News agencies say authorities will conduct an autopsy on Litvinenko's highly radioactive remains on Friday, under secure conditions.
Some information for this report was provided by AFP, AP and Reuters.