During the 1950s, Israel was frequently attacked by Palestinian fedayeen, nearly always against civilians, mainly from the Egyptian-occupied Gaza Strip, leading to several Israeli reprisal operations. In 1956, the United Kingdom and France aimed at regaining control of the Suez Canal, which the Egyptians had nationalized. The continued blockade of the Suez Canal and Straits of Tiran to Israeli shipping, together with the growing amount of Fedayeen attacks against Israel's southern population, and recent Arab grave and threatening statements, prompted Israel to attack Egypt. Israel joined a secret alliance with the United Kingdom and France and overran the Sinai Peninsula but was pressured to withdraw by the UN in return for guarantees of Israeli shipping rights in the Red Sea via the Straits of Tiran and the Canal. The war, known as the Suez Crisis, resulted in significant reduction of Israeli border infiltration. In the early 1960s, Israel captured Nazi war criminal Adolf Eichmann in Argentina and brought him to Israel for trial. The trial had a major impact on public awareness of the Holocaust. Eichmann remains the only person executed in Israel by conviction in an Israeli civilian court. During the spring and summer of 1963 Israel was engaged in a, now declassified diplomatic standoff with the United States due to the Israeli nuclear program.