TITLE 18—CRIMES AND CRIMINAL PROCEDURE
CHAPTER 118—WAR CRIMES
§ 2441. War crimes
(b) CIRCUMSTANCES.—The circumstances re-ferred to in subsection (a) are that the person committing such war crime or the victim of such war crime is a member of the Armed Forces of the United States or a national of the United States (as defined in section 101 of the Immigration and Nationality Act).
Nationality jurisdiction - national proceedings
EDIT.