IN VIEW of the continued testing by the Soviet Government, I have today ordered the resumption of nuclear tests, in the laboratory and underground, with no fallout. In our efforts to achieve an end to nuclear testing, we have taken every step that reasonable men could justify. In view of the acts of the Soviet Government, we must now take those steps which prudent men find essential. We have no other choice in fulfillment of the responsibilities of the United States Government to its own citizens and to the security of other free nations. Our offer to make an agreement to end all fallout tests remains open until September 9.
Note: Following the resumption of underground nuclear tests by the United States on September the White House released the following statement: President John F. Kennedy announced that the United States conducted an underground nuclear weapons development test of low yield at the Nevada Test Site at 1 p.m. The detonation has produced no fallout. This is in marked contrast to Soviet nuclear tests in the atmosphere.
The United States was forced reluctantly to make the decision to resume testing after years of attempting to reach a nuclear test ban with the Soviet Union when the Soviet Union without warning but after a great deal of preparation resumed testing in the atmosphere. We have announced ten such Soviet tests--three of them in the megaton range.
Today's test was the first in the joint Atomic Energy Commission-Department of Defense program to strengthen the defense of the free world. The resumption of extensive Soviet testing has made this action necessary to fulfill the responsibilities of the United States Government to its own citizens and to the security of other free nations.
In addition, as the program progresses, tests will be utilized to provide information in support of the U.S. programs to improve means of detecting and identifying nuclear explosions for possible use in an international nuclear test control system (Vela), and to study the use of nuclear detonations for peaceful purposes (Plowshare).
The United States once again affirms its readiness to negotiate a controlled test ban agreement of the widest possible scope.
John F. Kennedy, Statement by the President on Ordering Resumption of Underground Nuclear Tests. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/235570