A new policy laid out by the Trump administration has made marriage a requirement for partners of foreign diplomats to be eligible for a visa.
Foreign Policy magazine reports the administration has already begun denying visas to the unmarried, same-sex partners of foreign diplomats and employees of the United Nations.
"The Department of State will not issue a G-4 visa for same-sex domestic partners," a State Department memo reads. "As of 1 October 2018, same-sex domestic partners … seeking to join newly arrived U.N. officials must provide proof of marriage to eligible for a G-4 visa or to seek a change in such status."
The policy gives couples until the end of the year to get married. If they fail to comply, they must leave the country within 30 days of the Dec. 31 deadline.
Unmarried heterosexual partners are also not eligible for US visas.
Meanwhile, critics argue the policy fails to make allowances for those who come from countries that either ban same-sex marriage or only offer civil unions, thus creating an undue hardship.
"Those not yet in the country will need to show they're married to secure a visa, potentially forcing those living in countries without marriage equality to choose between a posting at UN headquarters or family separation," Akshaya Kumar, deputy UN director at Human Rights Watch, explained in a blog post.
But a State Department spokesperson explained that the policy shift is designed "to help ensure and promote equal treatment," NBC News reports.
The new policy went into effect on Monday.