sentences:  Moreover, Jewish policies of purchasing land and prohibiting the employment of Arabs in Jewish-owned industries and farms greatly angered the Palestinian Arab communities.Demonstrations were held as early as 1920, protesting what the Arabs felt were unfair preferences for the Jewish immigrants set forth by the British mandate that governed Palestine at the time.This resentment led to outbreaks of violence later that year, as the al-Husseini incited riots broke out in Jerusalem.