At least 31 people were killed in a fire that broke out amid clashes between pro-Russia demonstrators and government supporters in the southern Ukrainian city of Odessa.
The port city has not been a deadly flashpoint in the unrest that has plagued the eastern section of Ukraine during the tug-of-war between Russia and the West.
But violence erupted when protesters calling for a united Ukraine marched through the streets and were met by pro-Russian activists, Kiev-based UNIAN news agency and the Ukrainian online newspaper Ukrainskaya Pravda reported.
Riot police stepped in as the crowds threw flares and light bombs, and fired stones in slingshots. Several people were reported killed, but the toll rose sharply after a trade union building was set ablaze.
With flames roaring out of the doors and windows, occupants perched on ledges waiting for help.
The flare-up came as Ukraine troops were attempting to drive pro-Russian separatists out of Slovyansk, one of several cities across the east occupied by protesters opposing the new Kiev-government.
Read more at NBC News.