On May 16, Egypt made a military move, bringing troops into Sinai, near the Israel-Egypt armistice line, to supplement the troop force that Egypt ordinarily maintained in Sinai. Shams Badran, Minister of Defense, told Soviet Ambassador Dmitri Pozhidaev that Egypt wanted to have troops in place for an attack “that will begin immediately if Israel attacks Syria.” Egyptian Field Marshal Abdel Hakim Amer explained to Pozhidaev a deterrent aim: “Israel will not risk starting major military actions against Syria, because if it does Egyptian military units, having occupied forward initial positions on this border will immediately move out on the basis of the mutual defense agreement with Syria.”

Ambassador Yost shared Amer's analysis: “No doubt the Egyptian government decided sometime between May 13 and 16 that, in view of its assessment of the threat to Syria, it must move some of its armed forces up to the Sinai Armistice Line in order to deter Israel or to come to Syria's assistance if deterrence failed.” So too did Israeli Prime Minister Eshkol. On May 16, as the Egyptian deployment was under way, Eshkol told the Israeli cabinet: