Former Russian tycoon Mikhail Khodorkovsky has warned against the use of excessive sanctions against Russia by the West.

Khodorkovsky says the sanctions might have been necessary because of Russia's behavior on the international scene. But he says their use is a "tricky instrument" and that an excessive isolation of Russia "may play into the hands of" President Vladimir Putin's government.

Khodorkovsky, who spent 10 years in Russian prison before being released and moving to Switzerland last year, was speaking Sunday at the opening of a Forum 2000 conference in Prague. It is the 18th edition of the annual event established by late Czech President Vaclav Havel.

Khodorkovsky named visa restrictions as an example of sanctions to avoid.