London Hotel Staff Test Positive for Polonium-210

Three more London hotel workers have tested positive for low level exposure to the radioactive isotope that killed Alexander Litvinenko, health officials said today.

The news came as British police finished two weeks of investigations in Moscow into the suspected murder of the Russian former spy.

Tests on two staff members at the Millennium hotel in Mayfair, central London - which police suspect was the scene of Mr Litvinenko's poisoning - revealed small doses of polonium-210, the Health Protection Agency (HPA) said.

Exposure was also revealed by tests on an employee at the Sheraton hotel, Park Lane.

Previously, the HPA said Mr Litvinenko's widow, Marina, and seven members of staff at the Millennium hotel's Pine Bar had tested positive. However, one of the hotel workers was later shown to have normal levels of polonium.

Mr Litvinenko died on November 23 after receiving a huge dose of polonium-210. Before his death, he blamed the Russian government for the incident.

Police are examining a number of theories, including that he was targeted by powerful Russian figures acting independently of the Kremlin.

Andrei Lugovoi and Dmitry Kovtun, two Russian businessmen who met him at the Millennium hotel on November 1, have also been treated for suspected polonium-210 poisoning, according to reports.

Mario Scaramella, an Italian contact of Mr Litvinenko, has undergone treatment in London for the effects of contamination.

British police officers, who arrived in Moscow on December 4, "were shown complete and all-round assistance", the Russian prosecutor general's office said.

A statement said the officers had completed their enquiries, but did not specify when they would leave. It added that British police had been handed an array of material relating to the case, including transcripts of witness questioning.

UK investigators were not allowed to question witnesses themselves, but instead observed as Russian investigators conducted interviews.

Neither the Russian nor the British side have given details about who was questioned and whether any of those interrogated were regarded as suspects or simply witnesses.

However, Russian news reports said the questioning focused on Mr Lugovoi and Mr Kovtun.

German authorities found traces of polonium-210 at several locations in Hamburg visited by Mr Kovtun just before he flew to London for the November 1 meeting, as well as in his ex-wife's Hamburg flat.

Prosecutors in Germany are investigating Mr Kovtun on suspicion that he may have illegally handled radioactive material.

Mr Litvinenko once worked for the Federal Security Service, or FSB, one of the main successor agencies to the Soviet KGB. He broke his links with the agency in 1998 after accusing his superiors of ordering him to kill the tycoon Boris Berezovsky, and later fled to Britain.