A vice president of the European parliament has proposed restricting the convertibility of the Russian ruble as part of a package of measures to prevent Moscow making any further "aggressive" moves in Ukraine.

Ryszard Czarnecki, speaking at Poland's Sejm parliament, argued that Western sanctions against Russia have so far been a "reactive" response to Moscow's actions but that preventive measures would be more effective, according to a statement posted Wednesday on his website.

"To counter Russia's aggressive military actions, pre-emptive sanctions should be considered," Czarnecki said.

Following Russia's annexation of Crimea from Ukraine in March, the U.S. and EU have sanctioned dozens of Russian individuals and entities, many of whom have close ties to the presidency. The West has also accused Moscow of backing pro-Russian separatists in eastern Ukraine — a charge repeatedly denied by the Kremlin.

"Europeans must be wise before damage is done, not after the fact, and that's why we are proposing preventive sanctions instead of only those that present a response to Russia's actions," Czarnecki was quoted as saying by Polish daily Wyborcza Gazeta. "President Vladimir Putin must know what he has to fear, what awaits him."

Besides limiting the ruble's convertibility, Czarnecki also proposed reducing Europe's dependence on Russian oil and gas supplies.

The Moscow Times