Any real property purchased, constructed, altered, improved, or repaired with the proceeds of a guaranteed or insured loan shall be situated within the United States which for purposes of 38 U.S.C. chapter 37 is here defined as the several States, Territories and possessions, and the District of Columbia, the Commonwealth of Puerto Rico, and the Commonwealth of the Northern Mariana Islands. (Authority: 38 U.S.C. 3703(c)(1))