Ukraine conflict: Russian troops break into Sevastopol Navy base
2 March 2014 Last updated at 15:24 GMT
Armed troops have forced entry to an electricity supply room at the Ukrainian Navy's headquarters in Sevastopol.
Russian military activity in Crimea - home to Russia's Black Sea Fleet - has been increasing for the past few days.
Some 6,000 extra Russian troops and 30 additional armoured vehicles are now in Crimea, Ukrainian Defence Minister Ihor Tenyukh said on Saturday.