Citizenship status includes a person's immigration status. U.S. Citizens, U.S. Nationals, refugees, asylees, and recent lawful permanent residents (LPRs) are protected from citizenship status discrimination. There are two exceptions to this: (i) lawful permanent residents who do not apply for naturalization within six months of eligibility by virtue of their period of residency are not protected; and (ii) an employer may restrict hiring to U.S. citizen only if a law, regulation, executive order, or government contract requires the employer to do so. Further explanation of the types of discrimination can be found here.