Acting Secretary-General U Thant, in his Introduction to the Annual Report of the Secretary-General on the Work of the Organization, 16 June 1961—75 June 1962, stated that the serious situation in the Congo, which had led to the tragic death of Dag Hammarskjöld, was particularly crucial among the problems of the last year. The peace-keeping operation in the Congo (ONUC) and the UN Emergency Force (UNEF) had incurred large expenditures, while a number of Member States had failed to pay their assessments for the maintenance of these peace-keeping forces. As a result, the financial difficulties facing the Organization had become increasingly serious in the last year. In an effort to ease the UN's financial problems, the General Assembly had requested the International Court of Justice for an advisory opinion on the question of whether the expenditures for maintaining ONUC and UNEF constituted expenses of the Organization within the meaning of Article 17, paragraph 2, of the Charter and therefore represented binding legal obligations on Member States to pay their assessments for these operations. The General Assembly had also authorized the Secretary-General to issue during 1962 and 1963 up to $200 million of UN bonds.