evidence: Since the Arab-Israeli War of 1948, the Israelis had clashed intermittently with Palestinian Arabs and Arab forces from the neighboring states. By the mid-1960s, these incidents intensified causing increased diplomatic tensions in the Middle East. On April 7, 1967 a skirmish on land turned into a major air battle during which Israel shot down six Syrian MiG aircraft over Mount Hermon on the Golan Heights. This led President Gamal Abdel Nasser of Egypt immediately offered to assist Syria in the event of a future Israeli attack. [...] By the end of May, despite diplomatic efforts, tensions continued to rise. The withdrawal of the United Nations forces from the Sinai, the redeployment of Egyptian troops to the Sinai, the massing of hostile forces on the Israeli border, and the signing of a Mutual Defense Pact between Egypt and Jordan on May 30, weakened U.S. efforts to dissuade Israel from taking military action. The war began on June 5, 1967, when Israeli airplanes attacked the Egyptian air force and destroyed many airfields. Between June 5 and June 11, Israeli Defense Forces led onslaughts against Egyptian forces in Sinai and Gaza, and against the Jordanian military in East Jerusalem and the West Bank. The conflict ended with significant battles against Syrian forces on the Golan Heights between June 9 and 10. By June 11, Israel controlled territory previously held by the Arabs in the Sinai, the Golan Heights, the West Bank, the Gaza Strip and East Jerusalem.