Scientists examine corpse of former Russian spy

LONDON, Dec 1 (Reuters) British scientists will examine the corpse of a former Russian spy today to try to discover when and how he ingested a fatal dose of radioactive material.

The suspicious death of Alexander Litvinenko in London last month has heightened tensions with Moscow and sparked a police investigation that has found traces of radioactive material in 12 places and grounded aircraft in both countries.

Litvinenko, a British citizen who became an outspoken critic of Vladimir Putin after leaving Russia's secret service, accused the Russian president of ordering his killing. The Kremlin has denied any involvement and promised to help the British probe.

Three pathologists will attend Litvinenko's post-mortem at the Royal London hospital. The scientists will wear protective clothing and radiation levels will be monitored constantly during the examination.

Health experts said Litvinenko had ingested a significant amount of polonium 210, the highly radioactive isotope that killed him over a three-week period.

The head of Russia's state atomic energy agency Rosatom, Sergei Kiriyenko, told the government daily Rossiiskaya Gazeta that Russia produces only 8 grams of Polonium 210 a month and the material cannot be obtained illegally there.

Kiriyenko declined to say how polonium was produced but said nuclear reactors such as the Russian RMBK or the Canadian CANDU were needed to make it.

Investigators found traces of radioactivity on two British Airways planes that had flown between London and Moscow and a third BA aircraft will return to the British capital on Friday so police can scour it for signs of contamination.

The announcement about the planes and their destinations could rekindle suspicions of a Moscow link to the poisoning.

British police cleared one Russian plane after tests in London on Thursday, but they still want to check a second Russian aircraft as part of the probe.

The Health Protection Agency said passengers who had used the aircraft, being held at London's Heathrow airport, in the past month had not been at risk of radiation poisoning.

In a separate development, Russian doctors said they had identified no natural cause for an ailment afflicting former Russian Prime Minister Yegor Gaidar, who fell ill during a trip to Ireland the day after Litvinenko died.

Doctors said it was too early to say whether he had been poisoned, his spokesman Valery Natarov told Reuters.

Gaidar, an academic who has voiced restrained criticism of Putin's economic policies, is recovering in a Moscow hospital.

REUTERS PDM VV1558