Russia's chief prosecutor said on Tuesday that Moscow would not extradite to Britain possible suspects in the poisoning death of former agent Alexander Litvinenko, but would help British police investigate the case.

"If they want to arrest them it would be impossible, they are citizens of Russia and the Russian constitution makes that impossible," Prosecutor General Yuri Chaika told reporters after a meeting between Russian prosecutors and a group of British police probing Litvinenko's death.

The Scotland Yard officers arrived in Moscow on Monday to speak to several people who met Litvinenko around the time of his alleged poisoning in early November.

Litvinenko died of radioactive poisoning late last month in London. Experts investigating his death have found radiation traces at a dozen locations and on two British Airways planes that flew the Moscow-London route.

Italian security expert Mario Scaramella, who met Litvinenko the day he fell ill, has tested positive for traces of the same radioactive isotope believed to have killed Litvinenko.

Chaika said Russian prosecutors would question Litvinenko's business associate Andrei Lugovoi as part of the investigation. Lugovoi also met Litvinenko the day he fell ill in London.

"He is ill and currently in hospital. If doctors allow, then he will certainly be questioned," the Interfax news agency quoted Chaika as saying.

"We will do our utmost to help our British colleagues," Chaika said.

Litvinenko, who was a strong critic of Russian President Vladimir Putin, accused the Kremlin of orchestrating his poisoning just before his death. Moscow vehemently denies the charge.

The former agent, who had been arrested several times, fled to Britain with his wife and son in November 2000 and was granted asylum. He became a British citizen last month.

Foreign Minister Sergei Lavrov warned on Monday that politicization of the case could damage relations between Russia and Britain.

"The sole concern we are talking about today is the need to avoid politicizing that issue," Lavrov was quoted by the Itar-Tassnews agency as saying on a trip to Brussels.

He warned against officials' involvement in fueling the row over Litvinenko's death. "This certainly harms our relations," he said.

(Xinhua News Agency December 6, 2006 )