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Britain ordered the expulsion of four Russian diplomats today over Moscow's refusal to hand over the main suspect in the murder of ex-KGB agent Alexander Litvinenko, escalating tension between Russia and the West.
Russia said the decision was "immoral", would prompt retaliation and could only entail "the most serious consequences for Russian-British relations", according to a foreign ministry spokesman.
Aside from the expulsions - the first since 1996 - Britain said it would make it harder for Russian officials to come to the country and review cooperation on other issues. It said the case could harm Russian ties with the European Union as a whole.
"This is a situation the government has not sought and does not welcome. But we have no choice but to address it," British Foreign Secretary David Miliband told parliament.
Prime Minister Gordon Brown, speaking after meeting German Chancellor Angela Merkel in Berlin, said he wanted good relations with Russia, but also wanted justice to be served. He said he made no apologies for the diplomatic expulsions.
"We want to work together with Russia constructively on all the major international issues that we face," said Brown, mentioning Iran and the Middle East.
But, he added: "A murder did take place. It has been investigated by the independent prosecuting authorities. They have laid a charge and they have made it clear who they want to try for this crime.
"We're sad that the cooperation has not been forthcoming. We have therefore had to take the action that we have taken."
British prosecutors want to charge former Russian state security agent Andrei Lugovoy with the murder of Litvinenko, a British citizen who died in a London hospital after ingesting a lethal dose of the rare radioactive isotope polonium-210.
Russia has rejected Britain's request to hand over Lugovoy, saying its constitution does not allow extraditions of Russian citizens.
Russian President Vladimir Putin has said the demand is politically motivated. Lugovoy asserted his innocence on Monday.
"We have chosen to expel four diplomats, four particular diplomats, in order to send a clear and proportionate signal to the Russian government about the seriousness of this case," said Miliband, adding he was grateful for strong EU support.
"We will discuss with partners the need for future EU-Russia engagement to take our concerns on this case into account."
Both Washington and the European Union are at loggerheads with Moscow over issues ranging from missile defence and energy policies to the future of Serbia's Kosovo province.
Putin's decision at the weekend to suspend participation in a treaty limiting armed forces in Europe has further raised concerns about a new "Cold War".
Interfax news agency quoted an "informed source in Moscow" -- a traditional reference to high-level leaks -- as saying the Russian response would not necessarily be tit-for-tat.
"This is not our principle," said the source. "It would bring us back to the days of the Cold War. It's a shame that some have this principle entrenched deep in their minds."
Analysts echoed the sentiment, saying while the expulsions would provoke a robust response from Russia, they did not expect the row to escalate too far as it might harm commercial ties.
"I don't think they'll do anything that will jeopardise that," said Derek Averre, Russia specialist at Birmingham University. "There won't be a massive kind of escalation because it's simply not in Moscow's interests."
Moscow has dismissed as ridiculous Litvinenko's deathbed accusation that Putin ordered his killing.
Britain has rejected a Russian offer to put Lugovoy on trial at home, saying it doubts Moscow's promises of a fair trial.
In London, Alexander Goldfarb, a Russian emigre and close friend of Litvinenko's, expressed pleasure and surprise at Britain's decision to expel diplomats.
"It's a great, and appropriate, response ... I personally did not expect such a strong reaction."
CHRONOLOGY-THE CASE OF POISONED EX-SPY ALEXANDER LITVINENKO
Nov. 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 in Grosvenor Square. Traces of radiation were later found at both places.
Nov. 23 - Litvinenko dies of radiation poisoning. Traces of polonium-210 are found in his system.
Nov. 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.
Nov. 28 - British Prime Minister Tony Blair promises that "no diplomatic or political barrier" will be allowed to hamper the investigation into Litvinenko's death.
Dec. 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 Dec. 6.
Dec. 4 - British police fly to Moscow.
Dec. 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 in the same hospital where Lugovoy is being treated, apparently for radiation poisoning.
Dec. 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. Jan. 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.
Feb. 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 multimillionaire 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".
- REUTERS
