Litvinenko told the Italian academic Mario Scaramella, whom he met on the day he fell ill, that he had masterminded the transfer of radioactive material to Zurich in 2000 for his former Kremlin paymasters, The Independent said.

The operation would have been one of the last Litvinenko carried out while still an officer for Russia's Federal Security Services (FSB), the successor to the KGB, before his flight to Britain later that year, the newspaper added.

Scaramella's claims come as the co-author of Litvinenko's critical book "Blowing Up Russia: Terror From Within" alleged his friend had suspicions that the Italian had a hand in poisoning him.

"When I talked to Alexander around 12 November about who poisoned him, we were talking only about the Italian guy Mario," Yuri Felshtinsky was quoted as saying by The Sun tabloid.

"He was sure at this time it was Mario. He was telling me that he was in a scheme."

Scaramella, who has said his meeting with Litvinenko concerned an alleged FSB "hit list" on which both their names figured, has denied any involvement in the apparent poisoning.

Meanwhile, Scaramella was one of eight people sent for precautionary tests after large quantities of radioactive polonium 210 were found in Litvinenko's urine.

He was under police guard at a safe house somewhere in London after flying in from Rome but has vowed to do all he can to help detectives get to the bottom of the mystery.

Public health officials said Tuesday that 1,121 calls were received to a special hotline in the 48 horus to midnight Monday. Of those, 68 were deemed worthy of further investigation and eight referred for testing.

But the Health Protection Agency (HPA) maintains that the risk to the wider public "remains low".

The Metropolitan Police confirmed late Tuesday that a five-star London hotel and an office building in the upmarket Mayfair district of the British capital were the latest addresses to be examined as part of the investigation.

Polonium 210 had not been found at the Sheraton Park Lane Hotel in Piccadilly and the office building in Grosvenor Street, Mayfair.

But traces of the highly toxic substance had been found at two separate addresses nearby, one belonging to the exiled Russian billionaire Boris Berezovsky and the other to a security firm visited by Litvinenko.

The substance has also been detected at the central London sushi bar where Litvinenko met Scaramella on November 1, a hotel where the Russian dissident met two contacts for tea on the same day and his north London home.

Berezovsky -- whom Litvinenko alleged was a Russian intelligence target because of his criticism of the Kremlin -- said he was "deeply saddened" at his death..

"I credit him with saving my life and he remained a close friend and ally ever since," he said. "I will remember him for his bravery, his determination and his honour."

Russia has repeatedly denied any involvement in Litvinenko's death. Its prosecutor general's office has vowed to assist the inquiry but as of Tuesday said had not received a formal request.

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