The BBC's Claire Doole: "If found guilty Sergei Mikhailov could face up to seven and a half years in jail"

Sergei Mikhailov, 40, is alleged to head a Moscow-organised group called Solntsevskaya, which is implicated in drug trafficking, money laundering and other criminal activities.

As the trial opened under unprecedented security, the judge rejected a defence request for a postponement on grounds that media coverage of the case had been unfair.

Mikhailov was already wanted by the US, Israeli and Belgian police when he was arrested in Switzerland two years ago.

Security from the coutroom to the border

Political commentator Andrei Piontkowski: Who is Sergei Mikhailov?

The Russian businessman is charged with belonging to a secret criminal organisation, using false documents and breaking a Swiss law restricting foreigners from buying property

If convicted he faces up to seven years in prison.

BBC's Claire Doole: "Odds stacked against Swiss investigators"

"It is an exceptional trial and security has been reinforced from the courtroom to the border," said Geneva police chief Guy Baer.

"We have not had this type of security before. The nature of this trial is unique in Geneva."

The defendant is to be provided with a bulletproof vest for the journeys between prison and the courthouse.

His trial is expected to last two weeks and hear from about 80 witnesses.

Test case

Correspondents describe the trial as an important test for the Swiss law banning participation in criminal organisations, which came into effect in 1994.

The Swiss judicial authorities have complained of a lack of Russian co-operation in the inquiry. Federal prosecutor Carla Del Ponte went to Moscow this year to pursue the investigation.