BERLIN—Former Soviet President Mikhail Gorbachev says Russia's parliamentary elections scheduled for December won't be fair, and he blasted "authoritarian" rule in Russia in a Wall Street Journal interview.

Mr. Gorbachev said Tuesday that he believed an authoritarian government was necessary to pull Russia together in 2000 when Vladimir Putin first came to power. At the time, he brushed off concerns from a French colleague that Mr. Putin would "make a habit" of such tactics.

Now,...