MOSCOW (Reuters) - Britain on Monday made an official request to Russia to extradite the man suspected of killing ex-KGB agent Alexander Litvinenko with radioactive polonium-210, deepening a rift between the former Cold War foes.
British prosecutors said last week they wanted to bring Russian businessman Andrei Lugovoy before a British court to try him for the murder of Litvinenko, who died on November 23 after being poisoned with the rare radioactive isotope.
"I this morning delivered the extradition papers to the Russian Ministry of Foreign Affairs for the extradition of Mr. Lugovoy," British Ambassador Anthony Brenton told reporters.
"We look for an early and positive response from the Russian authorities to the extradition request."
Asked if they had received the documents, an official with the Russian prosecutor general's office said: "We confirm this."
Lugovoy, who has always protested his innocence, met Litvinenko in a London hotel on November 1, the day Litvinenko fell ill.
The murder of Litvinenko with a highly unstable radioactive isotope in London aroused memories of Cold War espionage and has threatened to derail relations between Britain and Russia, now tied by billions of dollars of trade.
Moscow has refused to hand over Lugovoy to Britain because Article 61 of the Russian constitution forbids the extradition of its citizens.
British officials argue that extradition arrangements exist with Russia since it signed up to the 1957 European Convention on Extradition in 2001.
Attorney General Lord Peter Goldsmith said last week that Lugovoy must face trial in Britain as Litvinenko was a British citizen and the poisoning took place on British soil.
"This is a very serious case: a murder has been committed in the United Kingdom. A lot of other people were endangered in the course of that murder," Brenton said.
A former Russian Federal Security Service (FSB) officer who obtained British citizenship, Litvinenko said in a message read out after his death that the Kremlin was behind his poisoning.
The Kremlin has said those accusations are nonsense and senior officials say the Litvinenko affair has been used by President Vladimir Putin's enemies to damage Russia's image.
Russian prosecutors opened their own investigation into Litvinenko's death and what they said was the attempted murder of Dmitry Kovtun, who along with Lugovoy met Litvinenko at the Millennium Hotel in Grosvenor Square on Nov 1.
Russia also sent detectives to London to interview Russian tycoon Boris Berezovsky and Chechen rebel Ahmed Zakayev, both friends of Litvinenko and both enemies of the Kremlin.
Lugovoy, who used to work for the KGB's ninth directorate which protected the Soviet elite, later worked as head of security for Berezovsky. He now runs a business in Russia.
Treated last year at a unit of a Moscow hospital that treated the victims of the 1986 Chernobyl nuclear disaster, he has refused to say if he had polonium poisoning.
Since being named as the chief suspect for Litvinenko's murder, Lugovoy has given interviews to Russian television channels just a short walk from the British embassy.
Looking confident and smiling, Lugovoy told the NTV television station on Sunday that he would defend his innocence in court.
He told Reuters last week by telephone that he was innocent but refused further comment. His advisers say they do not want to give more detailed interviews to foreign media.