5 USC 9904 - Special pay and benefits for certain employees outside the United States
The Secretary may provide to certain civilian employees of the Department of Defense assigned to activities outside the United States as determined by the Secretary to be in support of Department of Defense activities abroad hazardous to life or health or so specialized because of security requirements as to be clearly distinguishable from normal Government employment
(1) allowances and benefits
(A) comparable to those provided by the Secretary of State to members of the Foreign Service under chapter 9 of title I of the Foreign Service Act of 1980 (Public Law 96465, 22 U.S.C. 4081 et seq.) or any other provision of law; or
(B) comparable to those provided by the Director of Central Intelligence to personnel of the Central Intelligence Agency; and