The highly contentious ban on travel to the United States from six nations – three of them in Africa – went into effect at 0000 GMT, or midnight in Ghana and 3 a.m. Friday morning in Khartoum.

The ban affects travelers from Sudan, Libya and Somalia. The original “Protecting the Nation from Foreign Terrorist Entry into the United States” executive order, signed by U.S.  President Donald Trump on January 27, originally included a ban on travel from Iraq which has since been changed. The ban on the African nations, as well as Iran, Syria and Yemen, is preserved in the newly implemented law.

The provisions were met with condemnation and scathing criticism, both in the U.S. and abroad, for their targeted focus on majority-Muslim nations and the barriers placed on refugees seeking safety.

Immigration advocates and human rights organizations immediately challenged the legality of the ban, filing lawsuits in federal court jurisdictions that included America’s island state of Hawaii.

Lower courts barred the enforcement of the travel ban as written, but the U.S. Supreme Court partially reinstated the ban earlier this week. It was, therefore, announced that the ban would begin again on Friday, although Hawaii immediately launched a new legal challenge on Thursday night.

The Supreme Court placed new limitations, however, on exactly who is subject to the ban. The court determined that the ban “may not be enforced against foreign nationals who have a credible claim of a bona fide relationship with a person or entity in the United States.” Travel to visit family, or for documented students and foreign workers, remains protected under the Supreme Court’s temporary decision.

Travel from the specific nations was subject to a 90-day ban in the original order, and a cap of 50,000 global refugee admissions to the U.S. in 2017 replaced the previous Obama administration expansion.

The court plans to hear the full case in the fall.