Powerful political, economic, and military entities always distrust one another to at least some extent-not that that has to necessarily lead to a cold war or even perhaps hostility-. It is nothing new that allied states always wanted to make sure than have a "one up" advantage against their ally "just in case". Even if the Soviet Union had remained allied with the Nazi government in Germany you can't really think they would trust each other for very long. Even among the Axis there would have come a paranoid conflict stemming from fear that one side could potentionally "have a decisive advantage". Thus this is not suprising. The comments are perhaps the one suprising thing. There really was no need to announce it in much more than a minor fashion without fanfare.