British investigators probing spy poisoning want to return to Moscow

Russia's top prosecutor said British investigators have asked to return to Moscow as part of their probe of ex-security agent Alexander Litvinenko's poisoning death.

"Literally yesterday a new international investigative request from Great Britain arrived containing a request seeking permission for a group of British investigators probing the Litvinenko case to come to Moscow," Prosecutor General Yuri Chaika said.

• Poisoned spy's deathbed message to 'barbaric' Putin

Scotland Yard agents traveled to Russia in December, as part of their investigation into the killing of Litvinenko, a Russian ex-security agent who died of radiation exposure in a London hospital in November.

Friends and family of Mr Litvinenko have blamed the Russian government for his death and speaking today outside University College Hospital in London, his tearful father Walter said: "This regime is a mortal danger to the world."

In a statement, Alexander Litvinenko thanked the British public for their support and said he was "honoured to be a British citizen".

"I would like to thank many people. My doctors, nurses and hospital staff who are doing all they can for me; the British Police who are pursuing my case with vigour and professionalism and are watching over me and my family."