Israel was celebrating its Independence Day when the Israeli government received word that Egyptian president Gamal Abdel Nasser was moving heavy artillery into the Sinai Desert. Additionally, large numbers of Egyptian forces were crossing the Suez Canal into the Sinai Desert. The Egyptian government had put its army on alert for an upcoming war. Syria and Jordan, too, moved into a state of alert and announced that they would not sit by idly if Israel attacked Egypt.
On the next day, the Egyptians instructed the United Nations Emergency Force (UNEF), whose stated role was to serve as a buffer between Israel and Egypt, to leave the Sinai Desert. UNEF complied with this directive. A week later, Egypt closed the Straits of Tiran to Israeli vessels and any ships that transported military equipment to Israel. Israel considered this move as an act of war.
