A key witness in the poisoning death of former Russian security agent Alexander Litvinenko again failed to speak to investigators Friday, but his lawyer said his health wasn't preventing the interrogation, a Russian news agency reported.

In London, investigators closed in on the Millennium Hotel's Pine Bar — as evidence grew that it was the site where Litvinenko was poisoned with the deadly radioactive toxin polonium-210.

Andrei Lugovoi, who met with Litvinenko at the Millenium on the day the former KGB agent believed he was poisoned, has been due to testify since Tuesday after a team of Scotland Yard officers arrived in Moscow, but the interrogation has been postponed several times.

Litvinenko died in London on Nov. 23 after being poisoned with a rare radioactive substance, blaming the Kremlin — accusations that Russian officials vehemently denied. British police are treating his death as murder.

Doctors at a Moscow clinic have been examining Lugovoi for any signs of illness due to possible exposure to radiation.

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The Interfax news agency on Friday quoted unidentified medical sources as saying that checks of Lugovoi had shown that some of his organs malfunctioned, apparently as a result of a radioactive substance.

Lugovoi himself later told the ITAR-Tass news agency that he was feeling "normal."

"Doctors believe that I'm in stable condition," Lugovoi was quoted as saying. He said that conclusive results of his tests would be ready by the end of next week.

Lugovoi's lawyer, Andrei Romashov, said that his client's condition wasn't an obstacle to his interrogation, adding that he didn't know why the questioning didn't take place Friday.

Interfax reported Thursday that businessman Dmitry Kovtun, an associate of Lugovoi who also met with Litvinenko in London, had slipped into a coma after being questioned by Russian investigators and Scotland Yard detectives.

Romashov denied that report Friday, saying Kovtun's condition was "the same" as before and during the interrogation. The report was "aimed at creating a negative atmosphere around this case, to make a sensation out of it," Romashov told The Associated Press.

Interfax later Friday cited a source as saying Kovtun had regained consciousness but was in serious condition with radiation damage to his intestines and kidneys. It said Lugovoi was in much better condition than Kovtun but was also showing signs of contamination.

Lugovoi told ITAR-Tass that he didn't trust reports about Kovtun's condition and urged an end to "speculation" about their condition.

In a statement, the Russian Prosecutor General's Office said Kovtun had "developed an illness also connected with the radioactive nuclide (substance)."

Kovtun had not previously been reported to have been ill. It was not clear if investigators had been questioning Kovtun as a witness or as a potential suspect.

Scientists aiding the police inquiry which has spanned from Washington to Moscow were on Friday continuing to comb through the hotel's now quarantined Pine Bar, officers said.

Detectives had not confirmed the venue as the location of the ex-spy's poisoning, but now consider it integral to the case, a police official said on condition of anonymity because she was not authorized to discuss the inquiry.

All seven staff working at the hotel's Pine Bar on Nov. 1 — the day Litvinenko sipped tea in the Pine Bar and later fell ill — have tested for contamination with the rare radioactive polonium-210 element, Britain's Health Protection Agency said Thursday.

Around 200 customers of the hotel bar on Nov. 1 are also being contacted and offered tests, health officials said.

But site is only one stop on a radioactive trial that winds through some of the London's most exclusive districts. Police have confirmed traces of polonium at around a dozen locations — including three downtown hotels, Arsenal's soccer stadium and a business district office block used by self-exiled Russian tycoon Boris Berezovsky.

The latest venue contaminated with polonium was confirmed Thursday as the Parkes Hotel in London's Mayfair neighborhood — where Lugovoi stayed on Oct. 16.

But residents said health officials had quelled public fears with reassurances that the risks of widespread contamination were minimal.

"I'm not too worried. Everything is under control," said Stephanie Widorini, a 23-year-old student, ducking past the doorway of the Millennium Hotel.

"We're so geared up for terrorism that it's just another incident," Lesley Driscoll, 58, who works in an office near the hotel.

Dr. Michael Clark, of the health protection agency, said the poisoning likely was carried out at the hotel bar, explaining how the three Russians and bar workers had been exposed.

"People go to bars to drink, eat and smoke — all of which are possibilities for the poisoning," Clark told The Associated Press on Friday.

Litvinenko's friend Alex Goldfarb said the former spy sipped tea during the meeting, while Lugovoi said he recalls ordering a bottle of gin. Clark said polonium could have been discreetly added to food or drink.

"If it was some sort of liquid, it could have been — as in James Bond — a little magic capsule," Clark told reporters on Thursday.

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