Ukrainian government forces opened fire on pro-Russian militants Sunday in the eastern town of Krasnoarmeysk, killing one man, whom a regional separatist leader identified as a civilian.
Denis Pushilin, self-proclaimed leader of the "People's Republic of Donetsk," said troops sent by the government in Kiev to wrest back control of the rebellious region had earlier blocked access to the town to disrupt a referendum on independence that the Ukrainian government has declared illegal.
"They [Ukrainian troops] were impeding the referendum. Members of the elections commission have barely escaped," Pushilin told Russia's Itar-Tass news agency.
Russia Today television also reported a tense standoff in Krasnoarmeysk after the government troops blocked buildings where voting had been underway.
The Donetsk and Luhansk regions staged a vote Sunday, asking residents of the largely Russian-speaking eastern areas whether or not they supported declarations of independence from Kiev's rule.
A massive turnout suggested a large majority cast "yes" votes that could set the stage for secession and eventual annexation by Russia, as occurred in Crimea two months ago.
Western leaders had joined Kiev's rejection of the referendum as illegal and disruptive of efforts to seat a legitimate president with a May 25 national election.
Roman Lyagin, head of the Donetsk election commission, told reporters here earlier that the government troops had erected roadblocks into Krasnoarmeysk around 3 p.m., after more than 77% of the town's voters had already cast ballots.
Lyagin said polling stations in Krasnoarmeysk were closed early because of "security considerations." Government troops have been conducting an "anti-terrorism operation" since Easter in a campaign to drive separatist gunmen from the government buildings they have occupied for weeks to demand independence.
Associated Press reported that its photographer in the embattled town had seen two people lying motionless on the ground.