Radiation hunt after spy death
Police probing the death of the Russian ex-spy Alexander Litvinenko have called in experts to search for radioactive material, the Home Office has said.
Mr Litvinenko's death, in a London hospital on Thursday, is believed to be linked to the presence of a radioactive substance in his body, it said.
The Metropolitan Police are said to be looking for any residual material at a number of locations.
The Kremlin has denied Mr Litvinenko's claims that it was involved.
A further statement will be made at 1500 GMT when the Health Protection Agency holds a news conference.
It is understood that the post mortem examination on Mr Litvinenko has not been held yet.
The delay is believed to concerns over the health implications for those present at the examination.
The Home Office said anybody concerned should contact NHS Direct on 0845 4647, who have been briefed about this issue.
Friends have said Mr Litvinenko was poisoned because of his criticism of Russia.
In a statement dictated before he died, the 43-year-old accused Russian President Vladimir Putin of involvement in his death.
Mr Litvinenko had recently been investigating the murder of his friend, Russian journalist Anna Politkovskaya, another critic of the Putin government.
Mr Putin's spokesman Dmitry Peskov reiterated the Kremlin's earlier dismissal of allegations of involvement in the poisoning as "sheer nonsense".
Before Mr Litvinenko's death, police said they suspected "deliberate poisoning" was behind his illness.
Investigators have been examining two meetings he had on 1 November - one at a London hotel with a former KGB agent and another man, and a later rendezvous with Italian security consultant Mario Scaramella, at a sushi restaurant in London's West End.
Mr Litvinenko, who was granted asylum in the UK in 2000 after complaining of persecution in Russia, fell ill later that day.
In an interview with Friday's Telegraph newspaper, former KGB bodyguard Andrei Lugovoi said he had met Mr Litvinenko at the Millennium Hotel in Grosvenor Square but vigorously denied any involvement in the poisoning.
Mr Scaramella, who is involved in an Italian parliamentary inquiry into Russian secret service activity, said they met because he wanted to discuss an e-mail he had received.