Samih K. Farsoun, PhD, Professor of Sociology at American University, in his 1997 book Palestine and Palestinians, wrote the following:
"Palestinian discontent with the new British order [mandate] arose in April 1920 on the occasion of the Nabi Musa festival. A minor incident led to an assault by Palestinians on a procession of Jews. Although it was investigated by a British-appointed commission, the commission's recommendations were not published. Riots also occurred on May Day 1921 in a charged Palestinian and regional political climate: Arab discontentment with the results of the San Remo (Allied) conference, which awarded the eastern Arab mandates to Britain and France, led to political tension in Palestine, Syria, and Lebanon and a revolt in Iraq.
In Palestine mass Jewish immigration commenced in accordance with the British policy of establishing a Jewish national home. Palestinians perceived the arrival of 10,000 Jewish immigrants between December 1920 and April 1921 as a harbinger of the future. A riot that started in Jaffa between radical leftist and centrist Zionist groups quickly involved the Palestinians, who also attacked the immigration hostel, a symbolic target of their hostility. Forty-eight Palestinians and forty-seven Jews were killed and 219 people wounded. From Jaffa, Palestinian rioting spread to rural areas, fueled by wild rumors of Jews killing Arabs. Several Palestinians were killed by British soldiers in an effort to defend Jewish settlements."
Esco Foundation For Palestine, a research foundation, in its 1947 study Palestine: A Study of Jewish, Arab, and British Policies Vol. 2 contained the following:
1920 "When the Syrian Congress met in March, 1920, and elected Faisal as King of United Syria, the fires of Arab nationalism flared up in Palestine. To the Arabs, the Jews now appeared as the chief obstacle to the achievement of a union of Palestine with Syria in the newly created independent Syrian State. The Arabs in Palestine, moreover, had reason to believe that "the Government was with them," that is, that the British Administration would not look with disfavor on action which would demonstrate Arab opposition to the French and to the Zionists.
The Moslem festival of Nebi Musa provided the occasion for setting off the explosive forces. On this year the festival fell on April 4th. After several thousand pilgrims had arrived in Jerusalem, a political demonstration was staged in which a large picture of Faisal was displayed. Cries directed against the Jews were shouted by leaders in the procession, and agitators incited an attack. Marchers in the procession fell upon the Jews with sticks and knives; the Arab police remained passive or in some instances joined the rioting. The British troops finally succeeded in quelling the disorders and detained several hundred Arabs for the night in a mosque. Disturbances broke out again when they were released in the morning. The Government was finally forced to disarm the Arab police, proclaim martial law and hand over the control to the military. Order was not restored until two days after the outbreak."
1921 "An illegal parade of Jewish Communists clashed with the regular Labor Day procession of the Jewish Labor organizations which had been authorized by the Government. The excitement offered an opportunity for Arab bands to attack both. A bloody riot ensued, followed by a horrible massacre in the Immigration House at Jaffa and thirteen Jews were killed. On the outskirts of Jaffa, Joseph Chaim Brenner, a leading Hebrew writer, was murdered together with the whole family whom he had visited at the time. There were reprisals on the part of the Jews in and around Jaffa; a number were killed and many on both sides wounded.
The general excitement spread throughout the country; armed bands of Arabs attacked and looted several Jewish colonies. Petach Tikvah, the oldest Jewish agricultural settlement, which employed many Arab agricultural workers and which was reputed to have good relations with the Arabs, was subjected to a serious attack in which Bedouins of the neighboring Abu Kishk tribe participated. The attackers were about 2,000 strong and some of them had rifles, but the colony managed to defend itself for several hours until it was saved by a squadron of Indian cavalry which happened to be on the march from Jenin to Jaffa. Another attack was held up by a squadron of planes and then dispersed by an Indian regiment. About fifty Arabs were killed in the encounter and there were four deaths among the Jewish colonists. An attack against Rehovoth was repelled by the inhabitants.
The Civil Administration proved powerless to maintain order; the police, mostly Arab, proved unreliable. The troops had to be called in before order was restored. In all, 88 persons were killed and 238 wounded."