Thousands of citizens of US-allied nations in Europe and beyond may be barred from entering the US under President Donald Trump's travel ban, sparking a wave of outrage and fresh confusion that threatened to open an early rift across the Atlantic.
Yet the Administration also appeared to be doling out exceptions to nations such as Britain - playing a game of favourites among traditional allies that could risk long-standing relationships.
Following instructions from the Department of Homeland Security, the US embassies in Germany and France warned today that citizens of those countries who are also dual nationals of Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen - the seven mostly Muslim nations targeted by the ban - would fall under the travel ban, joining people who hold passports only from those countries.
The measure's full effect appeared unclear - even to the US embassies in Europe, where conflicting information circulated. The US Embassy in Paris, for instance, warned that even existing US visas granted to dual citizens would be revoked, while the US Embassy in Berlin suggested only that new visas would not be granted.
The Trump Administration, however, may be favouring the dual nationals of some Western nations - a turn of events that could further complicate the White House's already foundering relations with Europe.
After talks with the White House, British Foreign Secretary Boris Johnson, for instance, reassured his nation today that dual British nationals of the flagged Muslim nations have received an "exemption" from the travel ban.
A statement posted by the US Embassy in London initially contradicted that - saying visa issuance to dual nationals has been "suspended effective immediately until further notification". But later, the embassy took down its warning and reposted another confirming that British dual nationals were indeed "exempt".
"We have received assurances from the US Embassy that this executive order will make no difference to any British passport holder, irrespective of their country of birth or whether they hold another passport," Johnson told Parliament.
The advisories sowed more confusion over a travel ban denounced by critics as a haphazard religious test targeting Muslims - criticism rejected by the Trump Administration. Yet the indication that dual nationals could also be included raised the surprise prospect that even full citizens of friendly nations with deep ties to Washington may find themselves at least temporarily prohibited from entering the US.
The Trump Administration has sought to portray the order - which blocks entry to citizens of the seven Muslim-majority countries and to refugees from around the world for at least 90 days to allow for "extreme vetting" - as an attempt to weed out prospective terrorists. But German Chancellor Angela Merkel led the European protest yesterday, suggesting it targets Muslims and saying she would seek to defend the travel rights of all German citizens.
"The necessary and also resolute fight against terror does not justify in any way a general suspicion against people of a certain faith, in this case against people of Muslim faith, or people of a certain origin," Merkel said.
Alluding to the uncertainty surrounding the ban, she added, "The chancellery in co-operation with the Foreign Ministry is making all efforts to clarify the legal situation for the dual citizens affected and to strongly assert their interests."
The US guidance appeared to catch the Europeans off guard. German Foreign Ministry spokesman Martin Schäfer, for instance, began a news conference yesterday by saying he did not know whether dual German citizens of the seven countries targeted by Trump would be affected. Several minutes later, he told reporters than he had just received information that the US Embassy in Berlin had said those citizens would indeed be impacted.
The German Foreign Ministry said tens of thousands of German citizens are potentially affected. The number of other people impacted could surge far higher across Western Europe. In addition, Schäfer said the order has raised further complications. If a citizen of one of the seven targeted nations has a US green card and wants to visit Germany, "can we give him a visa?" he asked. "The condition for this would be that he can return."
The French Foreign Ministry issued a warning about travel to the US, mentioning the uncertainty of the regulations for dual nationals.
"To date, not all the practical consequences of this text have been clearly identified," the ministry said in a statement. "The situation remains highly evolving."
It left some dual citizens shocked, and others fearful over whether and how they could visit family in the United States.
"It's completely unbelievable that members of Parliament and millions of other people are treated like terrorists," said Niema Movassat, a lawmaker from Germany's Left Party who holds dual German and Iranian citizenship. He penned a sharp letter to the US Congress denouncing the move.
"This is not about combating terrorism, but about right-wing populism and fascistic action," he said.
Other European citizens with dual nationality fretted they would be unable to see family.
"Luckily I was there in 2015 to see my 97-year-old uncle, who died shortly after," the German actress Jasmin Tabatabai, a dual German-Iranian national, told the Frankfurter Allgemeine newspaper. "Half of my family lives in the US, and because I have an Iranian passport, I'm not allowed to enter anymore. . . . I don't know when I'm going to be able to visit my family in the US again. . . . Many families are torn apart; parents can't see their children anymore. Trump's decree is inhumane and unfair."
Omid Nouripour, vice-president of Germany's German-American parliamentary committee, said that he feared he would not be allowed to visit the US as long as the executive order remains in place. Nouripour was born in Iran and holds dual Iranian and German citizenship.
Long a strong advocate of closer German-American relations, he blasted the new order.
"It's dirty symbolism," Nouripour said of Trump's executive order. "It's the best boost jihadis could hope for. They can now pretend the West really is at war with Islam."
Authorities announced that Canadian citizens and permanent residents would continue to have access to the US as usual. David MacNaughton, the Canadian Ambassador to Washington, tweeted that dual citizens in particular would not be affected by the ban and that those travelling with a Canadian passport would go through a "normal entry [and] transit process." MacNaughton suggested that national security adviser Michael T. Flynn had confirmed this information to the Canadian Embassy in Washington.