The former prime minister of Ukraine says the EU must unite and convince Russia that it truly exists.
Yulia Tymoshenko says Russia must understand that the Ukraine is a full and independent state, and not just a region.
Speaking at the EPP congress in Dublin, Ms Tymoshenko said Europe could not stand by and watch its largest country "be torn to shreds".
Speaking through an interpreter, she said allowing a referendum on Crimea would threaten the stability of all of Europe: