The US has announced it will deny diplomatic visas to same-sex partners of foreign diplomats and United Nations employees.
The change went into effect on Monday, giving partners currently in the US until 31 December to leave, get married or otherwise change their visa.
It is a reversal of rules introduced in 2009.
Currently, 25 countries have recognised same-sex marriage. Homosexuality remains illegal in 71 countries.
The new Trump administration policy update was circulated in a United Nations (UN) memo.
The memo states: “As of 1 October 2018, same-sex domestic partners accompanying or seeking to join newly arrived United Nations officials must provide proof of marriage to be eligible for a G-4 visa or to seek a change into such status.”
G-4 visas are granted to employees of international organisations and their immediate families.
According to the State Department, “only a relationship legally considered to be a marriage in the jurisdiction where it took place establishes eligibility as a spouse for immigration purposes”.