Confusion reigned at airports around the world Sunday over exactly which citizens from the seven nations subject to President Donald Trump's immigration ban are still permitted to fly to the U.S.

Airlines at international hubs from Dubai to London Heathrow were grappling with the implications of three court rulings in the U.S. Saturday and Sunday that have temporarily blocked the enforcement of parts of Trump's executive order.

In the hours after the presidential edict, many airports imposed blanket bans on U.S. travel for citizens of Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen, with Amsterdam Schiphol turning away seven people with valid visas, and Cairo denying boarding to migrants accompanied by United Nations officials.

Throughout the U.S., security officials detained 109 people arriving from the seven countries, including some legal U.S. residents, until judges in Brooklyn, New York; Alexandria, Virginia; and Boston intervened. The Boston ruling, issued Sunday, requires U.S. officials to let passengers from all seven countries who have valid visas deplane and go on their way, though the ruling applies only in Boston.

'Nothing Has Changed'

Still, airports and airlines are coming to terms with the implications. A security official at the American Airlines Group Inc. check-in desk at Heathrow's Terminal 3 said Sunday that he'd seen news of the court rulings overnight, but that no further guidance had filtered through from the carrier's U.S. base. Passengers holding passports from the seven countries will therefore all be turned away, in line with the executive order.

"Nothing has changed," he said.

Meanwhile, White House chief of staff Reince Priebus said Sunday on NBC's "Meet the Press" that "the executive order doesn't affect green-card holders moving forward," in what seemed to be an adjustment to the administration's policy.

Airports like Heathrow, Amsterdam and their Persian Gulf rivals are especially affected by the presidential instruction because the seven countries affected have few or no direct U.S. flights, compelling people from those states to fly via such major hubs. Global airlines have struggled to comply after being caught flat-footed by the executive order, and U.S. carriers didn't get advance notice of the travel ban either, according to a person familiar with the matter.

Stuck Overseas

The court decisions came after a day in which students, refugees and dual citizens were stuck overseas or detained and some businesses warned employees from those countries not to risk leaving the U.S.