Some 600,000 Palestinians lived in the West Bank (occupied by Jordan) and another 356,000 lived in the Gaza Strip (occupied by Egypt) at the outbreak of the Six Day War. Hundreds of thousands of Palestinians also lived in refugee camps in Jordan, Syria and Lebanon. In 1964, the Arab League founded the Palestine Liberation Organization, headed by Ahmad al-Shuqayri, and largely controlled by Egypt. The 1964 Arab League summit also called for the deployment of a Palestine Liberation Army. Starting in 1965, the Syrian government supported Palestinian Fatah fedayeen (guerillas) attacks across the armistice line with Israel, greatly exacerbating Syrian-Israeli tensions leading up to the Six Day War. During the war, the Palestinian Division held the first line in the Gaza Strip, along with three Egyptian divisions. Though the Arab armies suffered crushing defeats at the hands of the Israelis, "the fedayeen, who had really provoked it, flourished as a result" of the war. "The war turned them into the only remaining focal point for Arab resistance to Israel at a time of despair and brought to their ranks large numbers of recruits" (Safran, 242-3).
Six Days of War: June 1967 and the Making of the Modern Middle East, Michael B. Oren, 2002