When the soviets entered the war in august 1945, which japanese-occupied territory did they invade?

hong kong
malaya
manchuria
mongolia

They invaded Manchuria, declaring war on Japan.

In August 8th, 1945, the Soviet Union invaded the Japanese-occupied territory of Manchuria.

Explanation:

After the dropping of the bomb in Hiroshima, by the United States, Japan  was expected to surrender without posing further conditions. That was not, immediately, the case. In order to surrender, they expected to receive guarantees about their post-war situation and future perspectives as a sovereign nation.

After the unexpected invasion of Manchuria by the Soviets, both the military part - still resisting - and the emperor, Hirohito, began to reconsider their terms for an act of surrender, which happened on September 2nd, 1945.