Demonstrators carrying Russian and Ukrainian flags march in Moscow on Saturday to oppose Russian President Vladimir Putin's policies in Ukraine. Large rival marches have taken place in Moscow over Kremlin-backed plans for Ukraine's province of Crimea to break away and merge with Russia.

KIEV, Ukraine — Two people were killed and several others wounded, including a policeman, in a shootout at the building of a far-right Ukrainian nationalist group, highlighting the tensions in the eastern part of the country that have erupted in Ukraine’s political turmoil.

Details of the Friday night shooting in the city of Kharkiv were murky, but local news reports said it broke out after a skirmish between pro-Russia demonstrators and their opponents.

Violence has escalated in Ukraine’s Russia-leaning east in recent days, as pro-Russia demonstrators have seized government buildings and clashed with supporters of the new Kiev government. At least one person died and 17 were wounded in clashes in the city of Donetsk on Thursday.

Tensions are also high in another region, the Black Sea peninsula of Crimea, where a referendum is to be held Sunday on whether to split off from Ukraine and seek annexation by Russia. The peninsula, where Russia leases a massive base for its Black Sea Fleet, has been effectively under control of Russian forces since last month after troops blocked off Ukrainian military bases.

Kharkiv, near the Russian border, is a hotbed of pro-Russia sentiment and opposition to the acting Ukrainian government that took power last month after Russia-friendly President Viktor Yanukovych fled the country in the wake of months of protests.

After the skirmish, according to the reports, there was gunfire outside a building housing the offices of several nationalist groups including Right Sector, which was one of the drivers of the protests against Yanukovych and that vehemently opposes Russian influence in Ukraine.