MOSCOW -- Russia said yesterday that it would expel four British diplomats and suspend counterterrorism cooperation with London in the latest step in a confrontation linked to the radiation poisoning death of a former KGB agent turned Kremlin critic.
Britain had announced Monday that it was expelling four Russian diplomats over Moscow's refusal to extradite Andrei Lugovoi, a Russian businessman accused of using polonium-210 to poison Alexander Litvinenko last year in London.
The British government also said that it would place restrictions on visas issued to Russian officials.
Moscow's response to the British action was "targeted, balanced and the minimum necessary," Foreign Ministry spokesman Mikhail Kamynin said.
Kamynin described London's actions as "provocative and unfriendly," and he said Russia would mirror Britain's steps on visa issues.
Moscow has asked London to explain what visa restrictions it will be placing on Russian officials, Kamynin said.
"Until clarification is given on the new practices, Russian officials will not be asking for British visas, and analogous visa requests by British officials will not be considered by us," he said.
It was not immediately clear whether the mutual expulsions and other actions by the two sides have set the stage for further escalation of the confrontation or a gradual winding down of tensions over the Litvinenko murder.
Russian President Vladimir V. Putin predicted yesterday that the conflict would ease.
"It is in our interest, both in the interest of Russia and in that of the U.K., that these relations should keep developing," Putin said in comments reported by the Russian news agency Interfax. "I'm sure that we will cope with this mini-crisis."
The Litvinenko case has particularly serious diplomatic implications because of the use of polonium-210 and because in a written statement prepared shortly before his death, Litvinenko accused Putin of ordering his killing. The Kremlin has dismissed the charge as "nonsense."
Most of the world's polonium-210 is manufactured in Russia, and it is not a substance easily acquired in the quantity used to kill Litvinenko.
There has been considerable speculation that Moscow could retaliate further against London by taking steps against British economic interests in Russia.
British Petroleum and Royal Dutch Shell, which is incorporated in Britain, are potential targets.
Putin and other top Russian officials have pointed out repeatedly that their nation's constitution bans extraditions of Russian citizens to other countries, a point that British officials appeared to ignore for weeks.
But Monday, British Foreign Secretary David Miliband suggested in Parliament that Russia could amend its constitution to make it possible to extradite Lugovoi. Kamynin ridiculed that suggestion yesterday.
"How can one demand that a sovereign democratic country change its constitution for the sake of handing over one suspect in the Litvinenko case?" he asked.
Article 61 of the constitution states that "a citizen of the Russian Federation may not be deported out of Russia or extradited to another state."
Britain has rejected the option of providing its evidence to Moscow and having Lugovoi put on trial in Russia.
David Holley writes for the Los Angeles Times.