Which Soviet official informed Japan's ambassador that the USSR had declared war on Japan in 1945?

Vyacheslav Molotov informed Japan's ambassador that the Soviet Union had declared war on Japan in 1945.

Molotov, the Soviet foreign minister, delivered the notice to ambassador Naotake Satō in the Kremlin on 8 August 1945. The Soviet government stated that it would consider itself at war with Japan from 9 August, when Soviet forces began their offensive in Northeast Asia.

The declaration followed the Allied demand in the Potsdam Declaration and a Soviet commitment made at Yalta to enter the Pacific war. Soviet forces attacked Japanese positions in Manchuria from several directions shortly after midnight on 9 August in the region's local time.

This event is often discussed alongside the atomic bombings of Hiroshima and Nagasaki, but it was a separate military and diplomatic development. The Soviet entry destroyed Japan's hope that Moscow might mediate a negotiated settlement and became one of the factors in the final surrender decision.