The Six-Day War, or the 1967 Arab–Israeli war (5–10 June 1967), was fought between Israel and a coalition of Arab states, primarily Egypt, Syria, and Jordan, in the context of the Arab–Israeli conflict. In the war, Israel captured and occupied the West Bank (including East Jerusalem) from Jordan, the Gaza Strip and the Sinai Peninsula from Egypt, and the Golan Heights from Syria.
Military hostilities broke out amid poor relations between Israel and its Arab neighbors, who had been observing the 1949 Armistice Agreements signed at the end of the First Arab–Israeli War. In 1956, regional tensions over the Straits of Tiran (giving access to Eilat, a port on Israel's southeastern tip) escalated in what became known as the Suez Crisis, when Israel, along with Britain and France, invaded Egypt over the Egyptian closure of maritime passageways to Israeli shipping, ultimately resulting in the reopening of the Straits of Tiran to Israel and the deployment of the United Nations Emergency Force (UNEF) along the Egypt–Israel border.
In the months before June 1967, tensions again became dangerously heightened: Israel reiterated its post-1956 position that another Egyptian closure of the Straits of Tiran to Israeli shipping would be a definite casus belli. In May, Egyptian president Gamal Abdel Nasser announced that the Straits of Tiran would again be closed to Israeli vessels. He mobilized the Egyptian military into defensive lines along the border with Israel and ordered the immediate withdrawal of all UNEF personnel.
The war began on 5 June 1967 with Operation Focus, an Israeli surprise attack consisting of a series of airstrikes against Egyptian airfields and other facilities as the UNEF was leaving the zone. Israel caught Egyptian forces by surprise and destroyed nearly all of Egypt's air force, giving Israel air supremacy. Simultaneously, the Israeli military launched a ground offensive into Egypt's Sinai Peninsula and the Egyptian-occupied Gaza Strip. After some initial resistance, Nasser ordered an evacuation of the Sinai Peninsula; by the fourth day of the conflict, Israel had occupied the entire Sinai Peninsula. Jordan, which had entered into a defense pact with Egypt a week before the war began, did not take on an all-out offensive role against Israel, but launched attacks against Israeli forces to slow their advance. On the fifth day, Syria joined the war by shelling Israeli positions in the north.
Egypt and Jordan agreed to a ceasefire on 8 June, and Syria on 9 June, and it was signed with Israel on 11 June. The Six-Day War resulted in more than 15,000 Arab fatalities; Israel suffered fewer than 1,000. Alongside the combatant casualties were the deaths of 20 Israeli civilians killed in Arab forces air strikes on Jerusalem, 15 UN peacekeepers killed by Israeli strikes in the Sinai at the outset of the war, and 34 US personnel killed in the USS Liberty incident, in which Israeli air and naval forces mistakenly assaulted a United States Navy spy ship.
When hostilities ceased, Israel had occupied the Golan Heights from Syria, the West Bank including East Jerusalem from Jordan, and the Sinai Peninsula and the Gaza Strip from Egypt. The displacement of civilian populations as a result of the Six-Day War had long-term consequences, as around 280,000 to 325,000 Palestinians and 100,000 Syrians fled or were expelled from the West Bank and the Golan Heights, respectively. Nasser resigned in shame after Israel's victory, but was reinstated after a series of protests across Egypt. In the aftermath of the conflict, Egypt closed the Suez Canal from 1967 to 1975.
After the 1956 Suez Crisis, Egypt agreed to the stationing of a United Nations Emergency Force (UNEF) in the Sinai to ensure all parties would comply with the 1949 Armistice Agreements. In the following years, there were numerous minor border clashes between Israel and its Arab neighbors, particularly Syria. In early November 1966, Syrian president Nureddin al-Atassi signed a mutual defense agreement with Egypt. Soon thereafter, in response to Palestine Liberation Organization (PLO) guerilla activity, including a mine attack that left three dead, the Israeli Defense Force (IDF) attacked the village of as-Samu in the Jordanian-ruled West Bank. Jordanian units that engaged the Israelis were quickly beaten back. King Hussein of Jordan criticized Egyptian President Gamal Abdel Nasser for failing to come to Jordan's aid and "hiding behind UNEF skirts".
In May 1967, Nasser received false reports from the Soviet Union that Israel was massing on the Syrian border. Nasser began massing his troops in two defensive lines in the Sinai Peninsula on Israel's border (16 May), expelled the UNEF force from Gaza and Sinai (19 May), and took over UNEF positions at Sharm el-Sheikh, overlooking the Straits of Tiran. Israel repeated declarations it had made in 1957 that any closure of the Straits would be considered an act of war or justification for war, but on 22-23 May, Nasser ordered the Straits to be closed to Israeli shipping. After the war, U.S. President Lyndon B. Johnson said:
If a single act of folly was more responsible for this explosion than any other, it was the arbitrary and dangerous announced decision that the Straits of Tiran would be closed. The right of innocent, maritime passage must be preserved for all nations.
On 30 May, Jordan and Egypt signed a defense pact. On 31 May, having earlier declined Hussein's invitation to send troops to Jordan, Iraqi president Abdul Rahman Arif agreed to deploy troops and armored units in Jordan to confront Israel. They were later reinforced by an Egyptian contingent. On 1 June, Israel formed a National Unity Government by widening its cabinet, and on 4 June the decision was made to go to war. The next morning, Israel launched Operation Focus, the surprise air strike that launched the war.
Before the war, Israeli pilots and ground crews had trained extensively in rapid refitting of aircraft returning from sorties, enabling a single aircraft to sortie up to four times a day, as opposed to the norm in Arab air forces of one or two. This enabled the Israeli Air Force (IAF) to send several attack waves against Egyptian airfields on the war's first day, overwhelming the Egyptian Air Force and allowing the IAF to knock out other Arab air forces the same day. This has contributed to the Arab belief that the IAF was helped by foreign air forces (see Controversies relating to the Six-Day War). Pilots were extensively schooled about their targets, memorized layouts in detail, and rehearsed the operation multiple times on dummy runways in total secrecy.
The Egyptians had constructed fortified defenses in the Sinai. These designs were based on the assumption that an attack would come along the few roads leading through the desert rather than through the difficult desert terrain. The Israelis chose not to risk attacking the Egyptian defenses head-on, instead surprising them from an unexpected direction.
James Reston wrote in The New York Times on 23 May 1967: "In discipline, training, morale, equipment and general competence his [Nasser's] army and the other Arab forces, without the direct assistance of the Soviet Union, are no match for the Israelis. ... Even with 50,000 troops and the best of his generals and air force in Yemen, he has not been able to work his way in that small and primitive country, and even his effort to help the Congo rebels was a flop."
On the eve of the war, Israel believed it could win a war in 3–4 days. The United States estimated Israel would need 7–10 days, with British estimates supporting the U.S. view.
The Israeli army had a total strength, including reservists, of 264,000, though this number could not be sustained during a long conflict, as the reservists were vital to civilian life.
Against Jordan's forces on the West Bank, Israel deployed about 40,000 troops and 200 tanks (eight brigades). Israeli Central Command forces consisted of five brigades. The first two were permanently stationed near Jerusalem and were the Jerusalem Brigade and the mechanized Harel Brigade. Mordechai Gur's 55th Paratroopers Brigade was summoned from the Sinai front. The 10th Armored Brigade was stationed north of the West Bank. The Israeli Northern Command comprised a division of three brigades led by Major General Elad Peled which was stationed in the Jezreel Valley to the north of the West Bank.