By 20 July 1960, 3,500 troops for ONUC had arrived in the Congo. The 3,500 consisted of 460 troops from the Ethiopian Army (later to grow into the Tekil Brigade), 770 troops from the Ghana Armed Forces, 1,250 troops from Morocco and 1,020 troops from the Tunisian Armed Forces. The first contingent of Belgian forces had left Leopoldville on 16 July upon the arrival of the United Nations troops. Following assurances that contingents of the Force would arrive in sufficient numbers, the Belgian authorities agreed to withdraw all their forces from the Leopoldville area by 23 July. The last Belgian troops left the country by 23 July, as United Nations forces continued to deploy throughout the Congo. The buildup continued, ONUC's strength increasing to over 8,000 by 25 July and to over 11,000 by 31 July 1960. A basic agreement between the United Nations and the Congolese Government on the operation of the Force was finalized by 27 July.