On 9 August 1945 the Soviet Union invaded Japanese-controlled Manchukuo and declared war on Japan. Battle-hardened Soviet troops and their experienced commanders rapidly conquered Japanese-held territories in Manchuria, southern Sakhalin (11-25 August 1945), the Kuril Islands (18 August to 1 September 1945) and parts of Korea (14 August 1945 to 24 August 1945). The Imperial Japanese government, vacillating following the bombing of Hiroshima (6 August 1945) and Nagasaki (9 August 1945), but faced with Soviet forces fast approaching the core Japanese homeland, announced its effective surrender to the Allies on 15 August 1945 and formally capitulated on 2 September 1945.