On 31 March 1958 , the Supreme Soviet of the Soviet Union approved a decision to halt nuclear testing , conditional on other nuclear powers doing the same . Khrushchev then called on Eisenhower and Macmillan to join the moratorium . Despite the action being met with widespread praise and an argument from Dulles that the US should reciprocate , Eisenhower dismissed the plan as a " gimmick " ; the Soviet Union had just completed a testing series and the US was about to begin Operation Hardtack I , a series of atmospheric , surface-level , and underwater nuclear tests . Eisenhower instead insisted that any moratorium be linked to reduced production of nuclear weapons . In April 1958 , the US began Operation Hardtack I as planned . The Soviet declaration concerned the British government , which feared that the moratorium might lead to a test ban before its own testing program was completed . Following the Soviet declaration , Eisenhower called for an international meeting of experts to determine proper control and verification measures — an idea first proposed by British Foreign Secretary Selwyn Lloyd
Operation Hardtack I
Operation Hardtack I
Partial Nuclear Test Ban Treaty