Simferopol: Russian forces have completed their takeover of the Ukrainian navy's assets in Crimea with the storming of the minesweeper Cherkasy.

The Ukrainian navy has been reduced to only 10 vessels, with the other 51 it held at the beginning of this month, including its only submarine, now flying the Russian flag.

The US military maintains a dolphin program, too. Credit:Reuters

But of all the Ukrainian military assets Russia has seized during the annexation, none is quite as unusual as the combat dolphin program.

The Soviet Union began training dolphins and other marine mammals to locate mines, mark underwater obstacles and detect - and if necessary kill - enemy frogmen in the 1960s. The program is shrouded in myth, but the dolphins are believed to have been trained to kill frogmen with special harpoons or knives fitted to their backs, or drag them to the surface to be captured.