These Islands are only RUSSIAN territory due to WW2.
The former USSR REFUSED to allow the United States to use Soviet/Russian territory, in our war against Japan, even though the USSR was our “ally” in the war against Germany.
(More history, the USSR helped to START WW2, through the Molotov-Ribentrop treaty, which divided Poland. The USSR only got upset with Hitler when Hitler took more of Poland than what he agreed to take!)
Anyway, I do not think that the former Soviet Union even “captured” these islands until AFTER we dropped the first A-Bomb!
They claimed they were not “at war” with Japan, but, after we saved their buts in Europe (Yes, they bled, but the USA paid for it with supplies and food, and we bled too!) -— AFTER we made it clear that Japan would not and could not win, then and only then did the USSR decide it, TOO, was “at war” with Japan!
Stalin was scared to death of a two front war with Germany and Japan. He did all he could to avoid any conflict with Japan.
Germany very nearly defeated Russia. Had Hitler not been insane, they probably could have.