The Ukrainian military said on Saturday that it had sunk a Russian submarine and damaged an S-400 anti-aircraft missile system in the illegally-occupied Crimean peninsula.

The military said its attack had significantly damaged four launchers of the 'Triumf' air defense system on Friday.

Ukrainian forces also successfully hit and sank the Russian "Rostov on Don" submarine in the Crimean port of Sevastopol, the military said.