Authorities found traces of radiation on two British Airways jetliners in London, grounded a third plane in Moscow, and asked passengers on more than 200 flights to come forward as investigators widened their search for clues in the poisoning death of former Russian spy Alexander Litvinenko. All three planes had been on the London-Moscow route, British Airways said. In the last three weeks the planes had also traveled to routes across Europe, including Barcelona, Frankfurt and Athens. Around 30,000 passengers had traveled on 220 flights on those planes, said Kate Gay, a spokeswoman for the airline. It said it had been told the risk to the public was low. Litvinenko, a former colonel with Russia's Federal Security Service, had been a fierce critic of Russian President Vladimir Putin before his death from radiation poisoning on Nov. 23. High doses of polonium-210 - a rare radioactive element usually manufactured in specialized nuclear facilities - were found in his body - and Britain's health protection agency began a screening program for people who visited the same venues as Litvinenko on Nov. 1. Traces of radiation have been found at six sites visited by the ex-spy. British Airways officials said the British government contacted them late on Tuesday and told them to ground the planes to allow investigators looking into the death of the former intelligence agent to test for radiation. Two planes at London's Heathrow Airport tested positive for traces of radiation. The third plane has been taken out of service in Moscow awaiting examination, the airline said. "The airline is in the process of making contact with customers who have traveled on flights operated by these aircraft, which operate within Europe," a British Airways statement said, adding, "British Airways understands that from advice it has been given that the risk to public health is low." The airline has published a list of the flights affected on its Web site, and told customers on these flights to contact a special help-line set up by the Health Ministry. In a deathbed accusation, Litvinenko blamed Putin for his poisoning, a charge Putin strongly denied. Britain's Home Secretary John Reid, who chaired a meeting of COBRA, the government's emergency committee, said that the tests on the planes were part of a wider scientific investigation into sites that could be linked to Litvinenko's death. Earlier on Wednesday, Italian security expert Mario Scaramella - one of the last people to see Litvinenko before he fell ill - said that tests have cleared him of radioactive contamination. Scaramella traveled from Rome to meet with Litvinenko at a sushi bar in London on Nov. 1 - the day the former intelligence agent first reported the symptoms that ultimately led to his death in the intensive care ward of a central London hospital. "I am fine," Scaramella told The Associated Press by telephone. "I am not contaminated and have not contaminated anybody else." Scaramella returned to London to undergo tests and talk with the police on Tuesday. He said he is in security protection and refused to say where he was. More than three dozen staff at the two hospitals that treated Litvinenko will be tested for radioactive contamination, Britain's Health Protection Agency said earlier on Wednesday. Media reports in Britain and Russia on Wednesday alleged that Litvinenko had been engaged in smuggling nuclear substances out of Russia. The Independent newspaper reported that Litvinenko told Scaramella on the day he fell ill that he had organized the smuggling of nuclear material for his former employers at Russia's Federal Security Service, or FSB. The newspaper reported that Litvinenko said he had smuggled radioactive material to Zurich in 2000. But Scaramella told the AP that he had been misquoted by the newspaper. "He (Litvinenko) wanted to see me because he knew about smuggling of nuclear material, but as far as I know he was never involved in nuclear smuggling," he said. London police say they are investigating the case as a "suspicious death" rather than murder, although they have devoted a large anti-terrorist force to the investigation. And Scaramella said he had been cleared of any involvement in the 43-year-old former spy's death. Scaramella said he showed Litvinenko e-mails from a confidential source identifying the possible killers of Russian investigative journalist Anna Politkovskaya and listing other potential targets for assassination - including himself and Litvinenko. A coroner will perform an autopsy on Litvinenko on Friday, "subject to appropriate precautions," in a bid to pin down the cause and circumstances of the death, said the local authority responsible, Camden Council. Doctors had sought expert advice on whether Litvinenko's radioactive body posed a threat to the doctors and technicians performing the post-mortem. A coroner's inquest will be opened Thursday and then adjourned until the police investigation is complete, the council said.