In furtherance of the purposes of this subchapter and subject to the provisions hereof, the Secretary of Housing and Urban Development may make loans or grants, or other payments, to public and nonprofit agencies for the provision, or for the operation and maintenance, of community facilities and equipment therefor, or for the provision of community services, upon such terms and in such amounts as the Secretary of Housing and Urban Development may consider to be in the public interest: Provided, That grants under this subchapter to any local agency for hospital construction may be made only after such action by the local agency to secure assistance under Public Law 725, Seventy-ninth Congress, approved August 13, 1946, as amended, or Public Law 380, Eighty-first Congress, approved October 25, 1949, as is determined to be reasonable under the circumstances, and only to the extent that the required assistance is not available to such local agency under said Public Law 725, or said Public Law 380, as the case may be: Provided further, That grants or payments for the provision, or for the maintenance and operation, of community facilities or services under this section shall not exceed the portion of the cost of the provision, or the maintenance and operation, of such facilities or services which the Secretary of Housing and Urban Development estimates to be attributable to the national defense activities in the area and not to be recovered by the public or nonprofit agency from other sources, including payments by the United States under any other provisions of this Act or any other law: And provided further, That any such continuing grant or payment shall be reexamined and adjusted annually upon the basis of the ability of the agency to bear a greater portion of the cost of such maintenance, operation, or services as a result of increased revenues made possible by such facility or by such defense activities.