Cement Incident took place in the port of Jaffa in Palestine on 16 October 1935 . While Arab dockers were unloading a consignment of 537 drums of White-Star cement from the Belgian cargo ship '' Leopold II '' , which were destined for a Jewish merchant called J. Katan in Tel Aviv , one drum accidentally broke open spilling out guns and ammunition . Further investigation by British Mandate officials revealed a large cache of smuggled weapons , comprising 25 machine guns ( Lewis guns ) , 800 rifles and 400,000 rounds of ammunition contained in 359 of the 537 drums , but because the merchant was not identified and the final destination was not uncovered no arrests were made . It was no secret that the Haganah had been smuggling arms into the country ever since the riots in 1929 and the discovery of the shipment gave credence to the claim that the Jews of Palestine were arming on a large scale . Since 1929 the Haganah had sent representatives to Belgium , France and Italy to purchase weapons which were often smuggled into Palestine in crates and luggage . A sharp sense of danger was thus derived from the perception that the Zionist movement was on the road to attaining the military capacity to establish its state
riots in 1929
1929 Palestine riots
Cement Incident