British police investigating the poisoning death of a former KGB agent have officially requested assistance from their Russian counterparts, prosecutors said, and officers were heading to Moscow yesterday to collect information.

Meanwhile, lawyers for another former security officer, Mikhail Trepashkin, who is now in prison in central Russia, appealed to the British officers to collect testimony as soon as possible. They said he possessed key evidence in the case, but that his life was in danger.

Alexander Litvinenko, 43, died on November 23 in London after ingesting radioactive polonium-210. In a deathbed accusation, he blamed Russian President Vladimir Putin for the poisoning. The Kremlin has vehemently denied the accusations.

In a letter from prison, Trepashkin, who is serving a four-year sentence for revealing state secrets, has said he had warned Litvinenko several years ago about a government-sponsored death squad that intended to kill him and other Kremlin opponents.

His supporters demanded yesterday that Trepashkin be given an opportunity to testify to the British police officers, saying he was not receiving adequate treatment for asthma in prison. "His life is in danger and he may die any night of asthma," said his lawyer Yelena Liptser.

Russian Foreign Minister Sergey Lavrov warned yesterday that continued suggestions of Russian official involvement in Litvinenko's death could damage relations with Britain.

Lavrov said he had spoken with British Foreign Secretary Margaret Beckett "about the necessity to avoid any kind of politicization of this matter, this tragedy," the RIA-Novosti news agency reported.

"If the British have questions, then they should be sent via the law enforcement agencies between which there are contacts," he said.

Russia's Prosecutor-General's office said in a statement that it agreed to help Scotland Yard officers in the investigation. A Foreign Ministry spokesman said Russia has issued visas for the team.

British Home Secretary John Reid, speaking during a trip to Brussels yesterday, said police had left for Moscow.

British law enforcement authorities had said a team of nine officers were to travel to Moscow.

Source: China Daily