Syrian refugees sit during an official welcome ceremony at Rome's Fiumicino international airport on Monday. Italian government and church officials have welcomed 41 Syrian refugees at Rome's airport, saying they wanted to show solidarity at a time when the United States is sending refugees away. (Alessandra Tarantino/AP)

Thousands of citizens of U.S.-allied nations in Europe and beyond may be barred from entering the United States under President 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 favorites among allies at the possible expense of long-standing relationships.

Following instructions from the Department of Homeland Security, the U.S. embassies in Berlin and Paris warned Monday that German and French citizens 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 U.S. embassies in Europe, where conflicting information circulated. The U.S. Embassy in Paris, for instance, warned that even existing U.S. visas granted to dual citizens would be revoked, while the U.S. Embassy in Berlin suggested only that new visas would not be granted.

The Trump administration, however, may be favoring the dual nationals of some Western nations — a turn of events that could further complicate the White House’s already floundering relations with Europe. After talks with the White House, British Foreign Secretary Boris Johnson, for instance, reassured his nation Monday that dual British nationals of the flagged Muslim nations have received an “exemption” from the travel ban.

Haya, a 13-year-old Syrian refugee from Homs, plays with balloons upon her arrival at Rome's Fiumicino international airport on Monday. Italian government and church officials have welcomed 41 Syrian refugees. (Alessandra Tarantino/AP)

The U.S. Embassy in London initially contradicted that Monday but later confirmed that British dual nationals were indeed “exempt.”

“We have received assurances from the U.S. 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.

The administration has sought to portray the order — which also blocks entry to refugees from around the world for at least 120 days to allow for “extreme vetting” — as an attempt to weed out prospective terrorists. But German Chancellor Angela Merkel suggested that it targets Muslims and said 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 Monday. Alluding to the uncertainty surrounding the ban, she added that Germany “is making all efforts to clarify the legal situation for the dual citizens affected and to strongly assert their interests.”

Who is affected by Trump’s travel ban

The U.S. guidance appeared to catch the Europeans off guard. The French Foreign Ministry issued a warning about travel to the United States, mentioning the uncertainty of the regulations for dual nationals.

German Foreign Ministry spokesman Martin Schäfer began a news conference Monday by saying he did not know whether dual German citizens of the seven countries targeted by Trump would be affected. Several minutes later, he said that according to new information from the U.S. Embassy in Berlin, those citizens would indeed be affected.

The 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 U.S. 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.”

Niema Movassat, a lawmaker from Germany’s Left Party who holds dual German and Iranian citizenship, penned a sharp letter to the U.S. Congress denouncing the move.

“It’s completely unbelievable that members of parliament and millions of other people are treated like terrorists,” he wrote. “This is not about combating terrorism, but about right-wing populism and fascistic action.”

Other European citizens with dual nationality fretted that they would be unable to see relatives.

“Luckily I was there in 2015 to see my 97-year-old uncle, who died shortly after,” actress Jasmin Tabatabai, a dual German-Iranian national, told the Frankfurter Allgemeine newspaper. “Half of my family lives in the U.S., and because I have an Iranian passport, I’m not allowed to enter anymore. . . . 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 Saturday that he feared he would not be allowed to visit the United States 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.”

It remained unclear whether officials such as Nouripour could yet find an out, since many lawmakers hold special diplomatic passports. The U.S. Embassy in Berlin could not immediately provide additional comment, although its advisory noted certain exceptions, including travel related to official government or North Atlantic Treaty Organization business.

Other countries around the globe also scrambled to assess the impact of the ban on their dual nationals, and it remained unclear whether the administration was granting exemptions to some nations and not to others.

Late Sunday, authorities announced that Canadian citizens and permanent residents would continue to have access to the United States 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 traveling with a Canadian passport would go through a “normal entry [and] transit process.” MacNaughton indicated that national security adviser Michael T. Flynn had confirmed this information to the Canadian Embassy in Washington.

In Australia, public broadcaster SBS reported Monday that an Australian Iranian teenager appeared to be the first dual national in the country affected by the ban. Pouya Ghadirian, 15, was attending a visa interview at the U.S. Consulate when he was advised that the new executive order would affect his travel.

“They were a bit shocked, and they didn't know how to handle it,” Ghadirian told SBS.

There were also widespread concerns about the ban in Israel. Israelis born in the countries listed by the executive order were warned by experts to avoid travel to the  United States.

“I recommend that Israelis born in these countries avoid traveling to the U.S. in the near future until we clear things up,” Liam Schwartz, a lawyer who specializes in American and Israeli immigration, told Ynetnews. “I don't think I'm exaggerating by saying this. The ban is unequivocal.”

Rick Noack in London, James McAuley in Paris, Stephanie Kirchner in Berlin and Adam Taylor in Washington contributed to this report.