(Reuters) - British police met Russian justice officials in Moscow on Wednesday as part of their probe into the Litvinenko poisoning, but there was still no sign they had been able to contact star witness, ex-KGB agent Andrei Lugovoy.
Russia's chief prosecutor Yuri Chaika on Tuesday virtually relegated British police to the role of observer and said it would be Russian authorities who would question witnesses in the case.
A team of British detectives arrived in Moscow on Monday to extend their inquiries into the November 23 death of Alexander Litvinenko, an outspoken critic of President Vladimir Putin, from radiation poisoning, reports Trend.
The detectives went into the headquarters of Russia's prosecutor-general on Wednesday morning, said a Reuters correspondent who saw them arrive.
But Prosecutor-General Chaika's comments at an ill-tempered news conference imposed stark restraints on their actions and it was not clear how they would proceed with approaching people they wished to question -- in particular Lugovoy who met Litvinenko the day he fell ill.
Commentators say the iciness of Chaika's remarks reflected poor relations soured by Britain's refusal to extradite Kremlin critics, such as millionaire Boris Berezovsky and Chechen separatist envoy Akhmed Zakayev.
Chaika also ruled out any extradition of potential suspects, saying any trial would be held in Russia, not Britain.
Lugovoy, a former KGB state security officer and now a businessman, staked out a role as a key figure in the affair by admitting to meeting Litvinenko in London on November 1.
Lugovoy says his meeting, that involved two other Russians, took place after Litvinenko made what appeared to be a fateful trip to a sushi bar where he met an Italian academic.
He denies any part in the poisoning that subsequently killed the 44-year-old ex-spy.
Police in London say traces of Polonium 210, the substance that killed Litvinenko over three weeks, had been found at the sushi bar and the Millennium hotel where the meeting with Lugovoy took place.
Apart from the bureaucratic hurdles that have sprung up, conflicting reports about whether Lugovoy is himself suffering radiation poisoning have also muddied the waters.
Russian media reported on Tuesday that Lugovoy might not be available to talk to the British detectives because he is in hospital being checked for radiation contamination.
Chaika said he would be questioned -- if doctors agreed.
Lugovoy, speaking to Russian journalists from an undisclosed location, is reported to be keen to cooperate with British police. But he says he has not been approached yet.
"I am ready to give testimony. All my telephones are switched on and I am not hiding from anyone. But no-one has called me yet," Moskovsky Komosomolets daily reported him as saying on Wednesday.
Lugovoy was an officer in the KGB state security service from the late 1980s when he was in charge of protecting senior Soviet officials and later training recruits into the Kremlin guard. He left the state security service at the end of 1996.