Background. In the mid-1950s, Israel undertook a determined effort to develop nuclear weapons. After Egyptian President Gamal Abdel Nasser closed the Straits of Tiran in 1953, Israeli Prime Minister David Ben Gurion began development of nuclear weapons and other unconventional munitions. His protege, Shimon Peres, played a central role in securing an agreement with France in 1956 for a nuclear research reactor. Physicist Ernst David Bergmann, director of the Israeli Atomic Energy Commission, provided early scientific direction. Because of Israel's precarious position in the Middle East, the bomb was considered a centerpiece of its security against hostile neighbors. On the eve of the Six-Day War in 1967, Israel “improvised” two deliverable nuclear explosive devices, according to Avner Cohen in his book, Israel and the Bomb.