the rolling Russian poisoning/assassination thread

But lawyers later denied that Dmitry Kovtun, a businessman and former Russian agent who met Litvinenko on the day he fell ill, had fallen into a coma.

The Associated Press quoted Interfax news agency saying Kovtun's condition worsened after he was questioned by British and Russian investigators.

A lawyer later said Kovtun's health was satisfactory, the Reuters news agency said.

Earlier, the Russian Prosecutor General's office said it had opened a criminal case into the death of Litvinenko, 43.

The move would allow suspects to be prosecuted in Russia. Officials previously have said that Russia would not allow the extradition of any suspects in the November 23 death.

British toxicologists found the rare substance polonium-210 in Litvinenko's body.

In another development Thursday, Britain's Health Protection Agency said seven workers at a London hotel had tested positive for low levels of the radioactive element.

The staff worked in the bar at the Millennium Hotel, where Litvinenko met a contact on the day he fell ill, AP said. It said there was no short-term risk to their health.

The Russian Prosecutor General's office also said it had opened a criminal investigation into the attempted killing of Kovtun, who was one of at least two Russian businessmen who met Litvinenko in London's Millennium Hotel on November 1, hours before the former spy fell fatally ill.

Kovtun and an associate, Andrei Lugovoi, have told the Russian media they went to London as part of a group of Moscow soccer fans, and met briefly with their exiled countryman to discuss business matters. Later, they attended a soccer game between CSKA Moscow and Arsenal at the Emirates Stadium in north London.

Both men have told reporters in Moscow that someone is trying to frame them in Litvinenko's death.

Meanwhile, a private funeral and a memorial service took place in London for Litvinenko.

Litvinenko was buried in a sealed airtight coffin to guard against any traces still in his body of the deadly polonium-210 radioactive isotope. (Ex-spy's funeral)

Around 50 family members and friends traveled to Britain from Russia and Italy to attend the ceremony, according to a family friend who spoke to AP.

Detectives investigating Litvinenko's death were expected to continue their inquiries in Moscow by questioning Lugovoi in the presence of Russian officials. (Watch as the radioactive trail leads to Moscow)

British police said Wednesday they were now treating the fatal poisoning case as a murder investigation.

Previously detectives had been treating the death from radiation of Litvinenko as suspicious.

"Detectives investigating the death of Alexander Litvinenko have reached the stage where it is felt appropriate to treat it as an allegation of murder," a statement from New Scotland Yard said.

"It is important to stress that we have reached no conclusions as to the means employed, the motive or the identity of those who might be responsible for Mr Litvinenko's death," it added.

Before his death in London the former FSB agent explicitly blamed Russian President Vladimir Putin for the poisoning.

The Kremlin has denied any involvement and Russian officials have pledged to give the British police all necessary support to carry out their inquiries. (Key players)

In a new development on Wednesday, traces of radiation were found in the British Embassy in Moscow, a British diplomat told Interfax news agency, according to AP. The find did not represent a heath risk, it said.

And polonium-210 has been detected at Arsenal's Emirates stadium in London that hosted a football match attended by Lugovoi, British officials said Wednesday.

Another contact who met Litvinenko on November 1, Italian intelligence consultant Mario Scaramella, "showed no symptoms of radiation toxicity" when he left a London hospital Wednesday, the hospital said.

Scaramella had met Litvinenko at a London sushi bar. Scaramella was admitted to University College Hospital Friday night, where he was undergoing tests. The hospital provided no further details on his condition.

In an exclusive interview with CNN before he left hospital Scaramella said he warned the ex-spy his life was in danger. (Full story)

"I received several e-mails from another source he [Litvinenko] introduced to me some years before, saying that him and me were under the special attention of hostile people, so to take care," Scaramella said.

He said he tried to warn Litvinenko that they were being targeted by "people linked with some clandestine organizations, not directly under control of Russian establishment but from Russia ... generally retired people from the security service."

The case has strained relations between Russia and Britain, who has given asylum to wealthy Kremlin critic Boris Berezovsky, Chechen rebel envoy Akhmed Zakayev, as well as Litvinenko.