Two Met Police officers working on the Alexander Litvinenko murder inquiry have tested positive for polonium-210.
Twenty-six officers closely involved with the investigation into the death of the former Russia spy were tested for traces of radioactive contamination. While 24 of the samples showed no evidence at all of radiation exposure, two showed traces of polonium.
The Met said the polonium traces were "relatively small" and were "below defined safety limits". It is understood that both officers are well and are continuing with their duties. They will be monitored by health specialists, a police spokeswoman said.
According to reports, Russian investigators are planning to travel to London to question witnesses in connection with Mr Litvinenko's death.
Moscow's Prosecutor General's office has outlined plans to send officials to Britain but was unable to confirm who they would question or when the interviews would take place.
A spokeswoman for the Moscow office said it was unclear when investigators would make the trip, adding: "There is no concrete date."
A team of nine Scotland Yard counter-terrorism detectives is in Russia to investigate Mr Litvinenko's poisoning in London last month.
Meanwhile in London, the police investigation appeared to focus on the Millennium Hotel where Mr Litvinenko met three Russian men on November 1, the day he fell ill.
Traces of polonium-210 are reported to have been found in a fourth-floor room, as well as in a cup from the hotel's Pine Bar. All seven staff working at the bar on the day of Mr Litvinenko's visit have been contaminated with polonium-210.
More than 200 customers and other people known to have been at the bar on November 1 will now be contacted and offered tests to determine if they have been contaminated with radiation.
