By Richard Galpin
BBC News, Moscow
Andrei Lugovoi, the focus of the UK probe into the murder of Alexander Litvinenko, has laughed off reports London may soon seek his extradition.
Mr Lugovoi met Mr Litvinenko the day police think he was poisoned
He told the BBC he had not read the Guardian report saying Scotland Yard had allegedly collected enough evidence for him to stand trial in the UK.
The former KGB officer has persistently denied any involvement in the murder.
Mr Litvinenko died on 23 November in London after taking a fatal dose of the radioactive isotope polonium-210.
The latest allegations to emerge from London have prompted Mr Lugovoi to speak once again to the media after weeks of silence.
But he had little to say, refusing to comment on the possibility of being extradited to Britain or that he could be swapped with the London-based Russian exile Boris Berezovsky, a leading opponent of President Vladimir Putin.
Mr Lugovoi said he was on holiday and resting. Last month he spent time in a Moscow hospital apparently being tested for radiation poisoning.
His admission to hospital coincided with the arrival of British detectives in the Russian capital investigating the Litvinenko murder.
But the team from Scotland Yard still managed to meet him twice, with Russian officials questioning him on their behalf.
Mr Lugovoi and another man, Dmitri Kovtun, are at the centre of the British investigation because they met Mr Litvinenko at a London hotel on 1 November - the day it is thought he was poisoned with polonium-210.
Eight hotel workers and another guest have tested positive for polonium.
The Interfax news agency has quoted a source at the office of Russia's prosecutor-general saying it is against Russia's constitution to extradite any of its citizens.