It's a territory.
Therefore, interestingly, congress has plenary power to govern them, and they do not get all of the rights of a citizen of the US, even though they are citizens of the US unless Congress extends the rights to them.
The Constitution doesn’t explicitly grant full constitutional protections to residents of territories. The Supreme Court, in cases like the Insular Cases (1901-1922), ruled that territories have “fundamental” rights (e.g., life, liberty) but not necessarily all rights (e.g., jury trials or equal protection), unless Congress extends them. For example, Puerto Ricans are U.S. citizens but lack voting representation in Congress.