At least one Ukrainian missile struck the headquarters of Russia's Black Sea navy in the Crimean port of Sevastopol on Friday, causing a fire, local governor Mikhail Razvozhayev wrote on the Telegram messaging app.
Separately, Russia's defense ministry said one serviceman was killed in the attack, while air defenses had downed a total of five missiles.
Razvozhayev said that although no further strikes were expected, locals were being urged to avoid the city center where the navy building is located. Firefighters were at the site, he said, and some roads were closed.
Razvozhayev said there were no civilian casualties or damage to civilian infrastructure.
Crimea is a frequent Ukrainian target
Crimea, which Russia seized and annexed from Ukraine in 2014, has been a frequent target of Ukrainian attacks in the course of the 19-month-old war.
Russian-installed authorities said air defense downed another missile on Friday near the town of Bakhchysarai. Crimea head Sergei Aksyonov said "cruise missiles" had been downed over the peninsula.