British Airways says it is grounding three of its aircraft in a widening investigation into the radioactive poisoning that killed a former Russian spy, Alexander Litvinenko.
The airline said in a statement Wednesday that slight traces of a radioactive substance were found on two planes. The third plane is in Moscow and will be tested.
The airline also said it is contacting more than 30,000 passengers who traveled on the planes over the last few weeks. It said the risk to the public is small.
The news comes as British authorities test at least eight individuals for traces of Polonium-210. It is the lethal radioactive substance that killed the former spy weeks after he ate at a London sushi restaurant.
One of those being tested is Mario Scaramella, an expert on Soviet-era KGB activities. He dined with Litvinenko at the restaurant on November 1.
Scaramella is reported to be under British police protection.
On Friday, a British coroner is scheduled to perform an autopsy on the body of the former Russian spy and Kremlin critic who died last week in a London hospital.
Authorities scheduled the post-mortem on Litvinenko after doctors determined that the ex-spy's poisoned remains do not pose a threat to the examining physicians and technicians.
Litvinenko died Thursday, after claiming he was poisoned for his opposition to Russian President Vladimir Putin. The Kremlin has denied any link to the case.
British Airways says it has set up a special helpline for concerned passengers.
Police have sealed off six locations with traces of polonium, including the London office of exiled Russian billionaire Boris Berezovsky and the sushi restaurant.
Some information for this report provided by AP, Reuters and AFP.
