BBC:
Former Russian spy Alexander Litvinenko has died in hospital three weeks after apparently being poisoned in London.
University College Hospital, London, said Mr Litvinenko had died at 2121 GMT on Thursday and the cause of his condition was still being investigated.
Friends have said the 43-year-old was poisoned because of his criticism of Russian President Vladimir Putin - Russia has denied any involvement.
Scotland Yard said they were now investigating "an unexplained death".
