Directly after Japan was nuked, what was the worlds reactions after learning about nuclear weapons?

The scientists who developed the atomic bombs felt tremendous remorse after the bombing. Many actually signed a petition that was given to Truman asking to not drop the bomb. Leo Szilard, the man who petitioned Roosevelt to start the atomic bomb project, was the man spearheading the campaign to not use it.

The atomic bombs were developed to stop Hitler, not the Japanese. It was believed that the Germans were developing their own nuclear devices (German scientists discovered fission) and we needed to build ours first.