The Ukrainian military announced its air force attacked the Russian Navy's Black Sea Fleet headquarters in Crimea which Moscow unilaterally annexed in 2014.

The General Staff of the Ukrainian Armed Forces said on Saturday that its air force had attacked the headquarters in the military port city of Sevastopol. It also struck Russia's air defense systems and places where Russian units, weapons and military equipment are concentrated within one day.

Russia's defense ministry said Friday that one of its servicemen was missing after the attack.

Ukraine's defense intelligence chief Kyrylo Budanov told local media at least nine people on the Russian side were killed, and 16 others, including a military commander, were injured.

He added the stepped-up attacks on Russia's military facility in Crimea indicate its air defense system is not working sufficiently.

Ukrainian forces are believed to be continuing attacks on Russia's military facilities on Saturday.

Ukrainian media say a fire broke out near the Black Sea Fleet's facility, and a senior Russian official in Crimea said on social media that fragments of a missile shot down by an air defense system had fallen.