A friend of poisoned former Russian intelligence officer Alexander Litvinenko on Thursday disputed two key witnesses' contentions that he was poisoned earlier than is widely believed.

Litvinenko's business associates Dmitry Kovtun and Andrei Lugovoi, who both met with him in London on Nov. 1 a few hours before he fell ill, have claimed the contamination actually took place not on that day, as Litvinenko believed, but in mid-October.

Kovtun, who was himself contaminated with radiation, and Lugovoi, who is undergoing radioactive checks, said their claims were supported by the fact that a London security firm they visited on Oct. 16 tested positive for radiation, arguing the poisoning could not have taken place on Nov. 1.

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They say it occurred in mid-October.

But Litvinenko's friend Alex Goldfarb told the Associated Press he was certain Litvinenko was in a perfect shape the morning before his meeting with Kovtun and Lugovoi, because a car he had driven in the day before later tested clean for radiation.

Lugovoi died on Nov. 23 in London and in a deathbed accusation blamed Russian President Vladimir Putin — an allegation the Kremlin strongly denied.

Russia's Aeroflot airline announced that it will check its planes that have flown to Hamburg for radiation contamination, spokeswoman Irina Danenberg told the AP.

She said the tests are being conducted at the request of German authorities in connection with the Litvinenko case.

Kovtun said Thursday that he would remain in a hospital for a few weeks. "As of today, my condition gives no serious ground for concern, but it would take doctors several weeks to determine a precise diagnosis," he told the ITAR-Tass news agency.

The chief prosecutor's office has said it plans to send investigators to London as part of the probe. Media reports said that Russian prosecutors wanted to question self-exiled tycoon and Kremlin foe Boris Berezovsky and Chechen rebel envoy Akhmed Zakayev who had close contacts with Litvinenko.

Berezovsky told the AP Thursday that he was ready to talk to Russian prosecutors provided that British officials check them for radiation and possession of harmful objects prior to the meeting. "I don't trust Russian authorities, they are capable of any kind of provocation," he said in a telephone interview from London.

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