After a period of relative calm, border incidents between Israel and Syria, Egypt, and Jordan increased during the early 1960s, with Palestinian guerrilla groups actively supported by Syria. In May, 1967, President Nasser, his prestige much eroded through his inaction in the face of Israeli raids, requested the withdrawal of UN forces from Egyptian territory, mobilized units in the Sinai, and closed the Gulf of Aqaba to Israel. Israel (which had no UN forces stationed on its territory) responded by mobilizing.
The escalation of threats and provocations continued until June 5, 1967, when Israel launched a massive air assault that crippled Arab air capability. With air superiority protecting its ground forces, Israel controlled the Sinai peninsula within three days and then concentrated on the Jordanian frontier, capturing Jerusalem's Old City (subsequently annexed), and on the Syrian border, gaining the strategic Golan Heights. The war, which ended on June 10, is known as the Six-Day War.
The Suez Canal was closed by the war, and Israel declared that it would not give up Jerusalem and that it would hold the other captured territories until significant progress had been made in Arab-Israeli relations. The end of active, conventional fighting was followed by frequent artillery duels along the frontiers and by clashes between Israelis and Palestinian guerrillas.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.