Puerto Rico is considered part of the US for licensure purposes, although it is not a state and has no representation in Congress.
There are four medical schools in PR; three of these are US medical schools, accredited by AAMC; thus, graduates are not foreign medical graduates (FMGs).
Universidad Central de Caribe SOM: class size 60; proficiency in both English and Spanish required. Most of class island residents.
Ponce SOM: class size 60; proficiency in both English and Spanish required. A little more than half the class island residents.
University of Puerto Rico SOM: strong preference for legal PR residents. Proficiency in both English and Spanish required. Highly qualified non-residents must demonstrate strong residential ties to PR; ad com reviews an applicants birthplace, HS attended, college attended and parent's legal residence. Only applicants meeting 3 of the 4 criteria will be sent secondaries. Class size 115; 2000-2001 entering class all in-state.
There is a fourth medical school (whose name escapes me at the moment) in PR. It has applied for AAMC accreditation several times but has not met AAMC standards. Only PR recognizes it. Graduates may become licensed to practice in PR, but are foreign medical graduates (FMGs) in the US and everywhere else in the world.
Medical schools in the US look closely at claimed URM status, especially during interviews.