June 5, 1942
White House news release.
Authoritative reports are reaching this Government of the use by Japanese armed forces in various localities of China of poisonous or noxious gases. I desire to make it unmistakably clear that, if Japan persists in this inhuman form of warfare against China or against any other of the United Nations, such action will be regarded by this Government as though taken against the United States, and retaliation in kind and in full measure will be meted out. We shall be prepared to enforce complete retribution. Upon Japan will rest the responsibility.