Ukraine claimed responsibility for a missile attack that struck the headquarters of Moscow's Black Sea fleet in annexed Crimea on Friday, sparking a huge fire and leaving at least one Russian serviceman missing.

The strike on the symbolic heart of Russia's Black Sea fleet marks a major blow for Moscow, which has suffered a string of attacks on the strategically important port in recent months.

Plumes of thick smoke could be seen pouring out of the Russian naval headquarters, footage shared on social media showed, while officials said missile fragments had fallen close to a nearby theater.