Gunfire at a Ukrainian military facility in the capital of separatist Crimea killed one serviceman and a member of a local self-defence brigade, a police spokeswoman was quoted as saying by the Interfax news agency.
Details of the Tuesday violence in Simferopol were sketchy, but the outburst underlined the high tensions over Crimea's weekend vote to split off from Ukraine and join Russia. Earlier Tuesday, Russian President Vladimir Putin signed an agreement to annex Crimea, which has a majority ethnic Russian population and is home to the Russian Black Sea under a lease with Ukraine.
Olga Kondrashova was quoted by Interfax as saying two other people were wounded in the gunfire at a remote-sensing and navigational facility.
Vladislav Seleznev, a spokesman for the Ukrainian armed forces in Crimea, said on his Facebook page that the facility was stormed by unknown armed men and that one serviceman was killed and another wounded.
A local news agency recently formed by pro-Russian Crimean authorities gave a different account, saying that snipers fired on self-defence units that had arrived to check out a report of armed men and that one of the self-defence brigade was killed.
Since Crimea's tensions soared three weeks ago, units of uniformed men without insignia have appeared, purportedly local residents defending their territory.
Russian forces effectively took control of Crimea after Ukraine's pro-Russia President Viktor Yanukovych fled the country in the wake of months of protests and sporadic bloodshed.
Crimeans overwhelmingly voted in a Sunday referendum to seek to join Russia, which it had been part of for centuries until Soviet leader Nikita Khrushchev transferred it to Ukrainian jurisdiction in 1954.