The Trump administration will no longer grant diplomatic visas to same-sex domestic partners of foreign officials or employees of international organizations, including the United Nations.

The policy, announced in July and went into effect on Monday, means couples already admitted to the U.S. will have to wed by Dec. 31 or leave the country within 30 days, impacting ambassadors, embassy or consulate aides, and applicable foreign military personnel.

The change was introduced so that U.S. visa guidelines reflect the nation's recognition of same-sex marriages, promoting "fairness among all of our diplomats," the State Department said in August to the Washington Blade, which first reported the policy.

The policy has been criticized by opponents including Samantha Power, a former Obama U.S. ambassador to the U.N., because so many other countries don't allow same-sex marriage.

Foreign Policy reported Monday that the Trump administration would make “limited exceptions” for diplomats from nations where same-sex marriage is illegal if their government provides evidence of the prohibition and permits same-sex partners of the U.S. foreign service corps. Exceptions, however, will not be applied to the U.N., the outlet reports.

Same-sex partners of foreign envoys and international organization staffers have been accepted by the U.S. since 2009 under then-Secretary of State Hillary Clinton, who served during the Obama administration.