A trade union building was attacked by protesters throwing rocks and petrol bombs, leaving at least 30 people dead in the aftermath.
In the video below, flames can be clearly seen in the lower floors of the building.
Unlike eastern Ukraine, Odessa had remained largely untroubled since the February toppling of President Viktor Yanukovych, who fled to Russia.
European Union foreign ministers added 13 people to their visa ban and asset freeze list over Ukraine's crisis.
Well that’s the voting over, and no surprises so far. A ‘Yes’ vote claimed to be 89% in Donetsk, and suddenly Ukraine is no more.
Nearly 90 percent of voters in eastern Ukrainian region voted for self-rule, the head of the separatist election commission said.