This repeated itself in many Jewish areas in Palestine both during the Ottoman rule and the later British mandate. It must be remembered that at that time there existed not one Arab country – there were no borders till after WWI. Droves of Arabs arrived from all over the Middle East, Persian Gulf, and Africa. Muslims of other ethnicities arrived from Africa and even Europe (to become part of the Arab group “described” today as “Palestinians”).
Of course Arabs also came from eastern Palestine - what later became Jordan when the British partitioned Palestine in the early 1920’s. They continued to this "in-migration" from eastern Palestine until the '48 war (those that went back to eastern Palestine during the war now refer to themselves as refugees and are so recognized the UN).