MOSCOW (Reuters) - Russia ordered the British government's cultural arm on Wednesday to halt work at its regional offices, in the latest round of a bitter dispute over the murder of Kremlin critic Alexander Litvinenko.
Relations between Russia and Britain hit their lowest level since the Cold War this year after Moscow refused to extradite a former KGB bodyguard who Britain suspects of poisoning Litvinenko in 2006 with radioactive polonium.
Russia said the British Council, which promotes British culture abroad, had breached international rules on consular activities by failing to properly register 15 regional offices.
Britain said Russia's move was illegal and the British Council had nothing to do with the row over Litvinenko's murder, which sparked a tit-for-tat expulsion of diplomats in July.
"This is a continuation of the exchange of measures which resulted from the Litvinenko murder," British Ambassador Anthony Brenton told Reuters by telephone.
"Why do the Russian authorities want to do something that their own people will suffer from?" Brenton said. "What Russia is planning to do is illegal."
Brenton said Britain "was very much hoping" that Russian would reconsider. British opposition politicians called on the government to lodge a protest with the Russian government.
Britain and Russia are linked by tens of billions of dollars in trade and bilateral investments -- including major stakes in oil projects held by BP and Royal Dutch Shell.
But in July, Britain expelled four diplomats in response to Russia's refusal to extradite Andrei Lugovoy to stand trial for Litvinenko's murder. Russia followed that by expelling four British diplomats.
Russia said its constitution forbids the extradition of its own citizens. Lugovoy has always denied having anything to do with the murder.
Russian Foreign Minister Sergei Lavrov said in an interview with the BBC released on Wednesday that Moscow's stance on the British Council was retaliation against Britain after the July expulsions.
"The British government undertook some actions which inflicted systemic damage to our relations so we have to retaliate," Lavrov said in the interview, a transcript of which was obtained by Reuters.
"This is nothing to do with anti-British sentiments. It's the law of the genre if you wish," Lavrov said.
Russia's Foreign Ministry ordered a halt to work at the British Council's offices from January 1 next year. It said the council had breached the 1963 Vienna Convention on consular activities, a claim denied by Britain's Foreign Office.
"It is a cultural, not a political institution and we strongly reject any attempt to link it to Russia's failure to cooperate with our efforts to bring the murder of Alexander Litvinenko to justice," a Foreign Office spokesman said.
"The Council's activities in Russia are fully compliant both with Russian and international law," he said, adding that a 1994 cultural agreement with Russia allowed the council to operate.
Its language teaching operations in Russia have already been crippled by allegations from the Russian tax authorities that it was not tax compliant. Britain disputes the allegations.
A British Embassy spokesman said the Council had earlier closed regional Russian offices everywhere except Moscow, St Petersburg and the Urals city of Yekaterinburg as part of a decision to refocus worldwide resources.
"The separate issue, which is what we're dealing with today, is the issue of Yekaterinburg and St Petersburg. The British Council has absolutely no intention of closing its offices there," the embassy spokesman said.