LONDON - Prime Minister Gordon Brown's new government ordered the expulsion of four Russian diplomats Monday over the Kremlin's refusal to extradite the key suspect in the fatal poisoning of a former KGB spy -- Britain's first use of the sanction in more than 10 years.
Russia quickly threatened retaliation, marking a new low point in Britain's relations with Moscow under President Vladimir Putin.
Alexander Litvinenko died Nov. 23 in a London hospital after ingesting radioactive polonium-210. In a deathbed statement, the 43-year-old accused Putin of being behind his killing.
British prosecutors have named Russian businessman and former KGB agent Andrei Lugovoi as the chief suspect. Litvinenko said he first felt ill after meeting Lugovoi and business partner Dmitry Kovtun at a London hotel.
But Russia has refused to extradite Lugovoi, saying its constitution prevents that.
Brown, speaking in Berlin, said, "I have no apologies for the action that we have taken, but I do want a resolution of this issue as soon as possible."
"When a murder takes place, when a number of innocent civilians were put at risk ... when an independent prosecuting authority makes it absolutely clear what is in the interest of justice and there is no forthcoming cooperation, then action has to be taken," the British leader said.
Foreign Secretary David Miliband told lawmakers in the House of Commons that "the Russian government has failed to register either how seriously we treat this case or the seriousness of the issues involved, despite lobbying at the highest level and clear explanations of our need for a satisfactory response."
Russia immediately threatened to retaliate.
"London's position is immoral," Russian Foreign Ministry spokesman Mikhail Kamynin said.
"They should understand well in London that the provocative actions conceived by British authorities will not go unanswered and cannot fail to produce the most serious consequences" for bilateral relations, he said.
Lugovoi said Monday the British decision "once again confirms that the Litvinenko affair had a political subtext from the very beginning," the Interfax news agency reported.
Russia formally rejected an extradition request a week ago, and British prosecutors then spurned an offer from Moscow to try Lugovoi there.
Lugovoi could be extradited under international agreements if he travels outside Russia, Miliband said. "The heinous crime of murder does require justice," he said. "This response is proportional and it is clear at whom it is aimed."
In Washington, State Department spokesman Sean McCormack said the Bush administration has urged Russia and Britain to cooperate on the case.
"We believe that it is important to bring closure to that terrible crime." McCormack told reporters. "We believe that it is important, as a matter of justice, to see some cooperation between the U.K. and Russia."
The Russian diplomats had yet to leave the country and the Foreign Office declined to provide their titles.
Britain also will place restrictions on visas issued to Russian government officials and is reviewing cooperation on a range of issues, Miliband said.
The expulsion order underlined how British-Russian relations have deteriorated since an initially promising start when Putin came to office in 2000.
Russia bristled at British criticism of its war in Chechnya, and later was irate at Britain's refusal to extradite Chechen separatist envoy Akhmed Zakayev and Boris Berezovsky, the tycoon and one-time Kremlin insider who fell out with Putin and obtained asylum in Britain.
In 2006, Russia accused four British diplomats of spying and funneling funds to non-governmental organizations critical of Putin's government.
Former Soviet leader Mikhail Gorbachev, who pursued closer relations with the West, said the expulsion order was a mistake.
"There have already been such instances in the history of our joint relations. They didn't lead to anything good," he was quoted as saying by the news agency Interfax.
One senior British diplomat, who demanded anonymity because of the sensitivity of the situation, said he hoped Russia would not react by jeopardizing delicate discussions over the future of Kosovo or Iran's nuclear ambitions.
Moscow would likely respond by expelling three British diplomats, said Oleg Gordievski, a former KGB defector to Britain.
Litvinenko's widow Marina said in a statement that she was grateful for the government's stand.
"It makes me proud to be a U.K. citizen because I can see that my strong faith in the British authorities was well-founded and that they too share my determination," she said.
Litvinenko's friend Alex Goldfarb said the British action was encouraging.
"Hopefully this strong response will be the beginning of a policy change," Goldfarb said. "The murder of Litvinenko was made possible by years of appeasement of Putin's regime by Western governments."
Russia's ambassador to London met with Sir Peter Ricketts, a senior aide to Miliband, shortly before lawmakers were told of the measures being taken against Moscow.
Britain and Russia last clashed over diplomatic expulsions in March 1996, when Moscow expelled nine British diplomats alleging that they were part of a spy ring. Britain kicked out four Russians in response.
"If anyone was under the illusion that the Gordon Brown government would take a softer stance on Russia than its predecessor, they no longer should be," said Andrew Kuchins, director of the Russia and Eurasia Program at the Center for Strategic and International Studies in Washington.
"While we most definitely are not in a new Cold War, it is very chilly in Russian-British relations," he said.
