TIMELINE: The case of poisoned ex-spy Alexander Litvinenko
(Reuters) - Russia said on Thursday it would expel four British diplomats from Moscow in retaliation for Britain's decision earlier this week to send home four Russian diplomats.
The British move came after Moscow refused to extradite Andrei Lugovoy, main suspect in the murder last year of Alexander Litvinenko, a former Russian intelligence officer living in Britain.
Here is a timeline of events:
November 1, 2006 - Litvinenko complains of feeling unwell after a day spent with contacts. After meeting the Italian Mario Scaramella at a sushi bar in London's Piccadilly, he saw former KGB contacts Lugovoy and Dmitry Kovtun at the Millennium Hotel. Traces of radiation were later found at both places.
November 23 - Litvinenko dies of radiation poisoning. Traces of polonium-210 are found in his system.
November 24 - Litvinenko accuses Russian President Vladimir Putin of his murder in a statement read out by friends the morning after his death. Putin brushes off the accusation.
November 28 - British Prime Minister Tony Blair promises that "no diplomatic or political barrier" will be allowed to hamper the investigation into Litvinenko's death.
December 1 - Pathologists carry out a post mortem on Litvinenko's body.
-- Scaramella is admitted to hospital in London and traces of polonium-210 are also found in the urine of Litvinenko's widow Marina. Scaramella leaves hospital on December 6.
December 4 - British police fly to Moscow.
December 6 - British police say they are now treating Litvinenko's death as murder.
-- British police and investigators from Russian prosecutor-general's office question Kovtun.
December 7 - Litvinenko is buried in London's Highgate Cemetery.
-- Russian prosecutors launch their own murder investigation. Prosecutors also open a criminal case into what they say was the attempted murder of Kovtun.
January 9, 2007 - Russia announces that Lugovoy was discharged from a Moscow hospital at the end of December. Lugovoy declined to say whether he had been contaminated with polonium-210.
February 1 - President Putin says that Litvinenko knew no official secrets and had no reason to leave Russia.
May 22 - British prosecutors name Lugovoy, a businessman who formerly worked for the Soviet KGB, as the man who murdered Litvinenko with radioactive polonium.
May 28 - Britain confirms that a formal request had been made to Moscow for Lugovoy's extradition.
May 31 - Lugovoy denies involvement at news conference, saying British intelligence and self-exiled Russian businessman Boris Berezovsky are more likely suspects.
July 5 - Russia officially turns down Britain's request to extradite Lugovoy.
July 16 - Britain says it will expel four Russian diplomats and suspend negotiations on facilitating the issue of visas. Russia calls the decision "immoral".
July 19 - Russia says it will expel four British diplomats. Moscow also says it will stop issuing visas for British officials and that recent British statements make continued cooperation on fighting terrorism impossible.
