British newspapers have published a U.S. diplomatic cable detailing Russian efforts to track the possible killers of former KGB officer Aleksandr Litvinenko, but their efforts were discouraged by Britain prior to Litvinenko's death.
The case severely strained British-Russian relations, with Moscow refusing to extradite Britain's prime suspect, former KGB officer Andrei Lugovoi.
The cable released by the whistle-blowing website WikiLeaks -- dated December 2006, one month after Litvinenko was poisoned by a rare radioactive isotope -- details a meeting between Russian special presidential representative Anatoly Safonov and U.S. Ambassador-at-Large Henry Crumpton.
In the memo, Safonov is said to have claimed that "Russian authorities in London had known about and followed individuals moving radioactive substances into the city but were told by the British that they were under control before the poisoning took place."
compiled from agency reports