MOSCOW, April 11 - RAPSI. The UK's request to classify a large part of the case materials on former Russian security agent Alexander Litvinenko's death in 2006 has raised concerns in Russia, Foreign Minister Sergey Lavrov said in an interview with the RTVI television channel.

Russia is interested in establishing the true reasons for Litvinenko's death, he stressed.

Alexander Litvinenko, a former KGB agent, defected to the UK in 2000. He died in 2006 shortly after meeting with former colleague Andrei Lugovoi in London's Millennium Hotel. It was announced soon afterwards that Litvinenko was poisoned with highly radioactive polonium-210, traces of which was found in his body.

Andrei Lugovoi, a Russian businessman and lawmaker, is the main suspect in Litvinenko's death.  However, Lugovoi has denied the accusations, claiming they are politically motivated.