Pussy Riot stars Nadezhda Tolokonnikova and Maria Alekhina have stepped up their protests over the ongoing Ukraine crisis by calling for economic sanctions against Russia.

The punk stars made an appearance at Tallinn Music Week in Estonia on Friday (28Mar14) amid heightened tensions in Eastern Europe following the arrival of Russian troops in Ukraine's Crimea region.

Alekhina, who has previously voiced her support for Ukraine, was joined by her Pussy Riot co-star Tolokonnikova, and she revealed plans to urge the European Parliament to impose economic sanctions on their native country.

She is quoted by NME.com as saying, "Tomorrow we plan to be in (Ukrainian capital) Kiev in order to support Ukraine. Then we go to the European Parliament to call for sanctions against Russia. It must be understood that economic sanctions will hurt ordinary Russians, but maybe it has got to the point where Russians are too comfortable sat on the couch, and this will shake them and force them out onto the streets to express their opinions...

"We do not invite anyone to use weapons against weapons. Our idea is that Europe and other countries have to use economic sanctions against (Russian president Vladimir) Putin."

Putin sparked international concern when he moved troops into the Crimean region of Ukraine earlier this month (Mar14) following weeks of unrest in the country.

Crimean residents voted in favour of breaking away from Ukraine and joining Russia in March (14), and Putin approved the decision to reclaim Crimea as a Russian territory. United Nations officials declared the referendum illegitimate on Thursday (27Mar14).