The Secretary (with the concurrence of the agency concerned) may assign a member of the Service to any position classified under section 3981 of this title in which that member is eligible to serve (other than as chief of mission or ambassador at large), and may assign a member from one such position to another such position as the needs of the Service may require.

In making assignments under paragraph (1), the Secretary shall assure that a member of the Service is not assigned to or prohibited from being assigned to a position at a post in a particular geographic area, or domestically, in a position working on issues relating to a particular country or geographic area, on the basis of the race, ethnicity, or religion of that member.

Foreign Service positions may be filled by the assignment for specified tours of duty of employees of the Department and, under interagency agreements, employees of other agencies; and

Senior Foreign Service positions may also be filled by other members of the Service.