One whole section of the General Groves book is on the subject of "Alsos II" - this was the allied effort to ferret out whatever could be found on Nazi secret weapons after VE day. The general consensus was that they were able to make limited amounts of dangerous refined radioactive materials, but were literally years from developing an actual nuclear bomb. The Japanese were considered to be decades further away - the limited equipment mentioned earlier here was actually for basic research, not even nearly as advanced as the German effort.
The Alsos team got all the German scientists together, held them after the war in a country estate in England, and secretly taped their reactions when the news of the Hiroshima blast was revealed to them. They all took several days to get over their shock that the allies had actually done it. They also revealed ignorance of the amount of material needed, or a real grasp of the engineering required.
One might say "thank God" given the jet planes, tanks, submarines, and rockets they turned out.
James