Iraq’s national soccer team landed at Chicago’s O’Hare airport last week in jubilant spirits to compete in the World Cup for the first time in 40 years.
For Aymen Hussein, among the top players in Iraqi history, his time on soccer’s biggest stage appeared, for a few tense hours, like it might slip away before it had even started. The striker watched his teammates leave for their base camp while immigration officials detained him for questioning. After several hours, the officials cleared Mr. Hussein.
Omar Abdulkadir Artan, a Somali referee, was not as fortunate. Mr. Artan, among a select group of about 50 World Cup referees, was also detained and became another example of how U.S. immigration policy could upend the world’s biggest sporting event.
Immigration officials questioned Mr. Artan, placed him in a holding cell and then deported him.
The two incidents have brought renewed scrutiny on Washington’s immigration and border policies, which have tightened under the Trump administration just as the United States prepares to host the most watched global sporting event.
On the eve of the tournament, immigration issues have emerged as an obstacle to a World Cup that was awarded to North America in 2018 with promises of inclusivity. The event is now being threatened by concerns of restrictive entry into the United States that critics had raised for years and soccer’s governing body, FIFA, had continually played down.
In February, Gianni Infantino, FIFA’s president who describes himself as a friend of President Trump, insisted the entry process would be “smooth.”
“I think it’s important to clarify this, there is a lot of misconception out there. Everyone will be welcome in Canada, Mexico and the United States for the FIFA World Cup,” he said.
But since then various groups connected to the World Cup — from players to fans to media professionals — have found the process anything but smooth.
Scores of journalists, mainly from the Middle East and Africa, have failed to get clearance to cover the World Cup, prompting a complaint to FIFA from a global umbrella body for sports journalists. Fans from Europe to Africa have also been hit with changing rules regarding entry, including a group of ticket holders from the Democratic Republic of Congo, who are now barred because of the outbreak of Ebola and unable to get a refund on their World Cup tickets.
Iran’s fate at the World Cup has been shrouded in uncertainty ever since the United States and Israel began a joint assault on the country at the end of February. Iran’s players were finally issued entry visas for their games in the United States, but more than a dozen team officials and staff members have had their applications rejected.
But it is the case of the Somali referee, Mr. Artan, that has sparked the most intrigue. He had traveled from Turkey to Miami and, according to an interview he gave to The New York Times, was deported back to Turkey. Last year, he was named the best referee in Africa by the region’s governing body for soccer.
For referees, the World Cup is considered the pinnacle moment of a career, as it is for players. Mr. Artan said the “biggest dream of my life” had been snatched away. He said all his paperwork was in order, but American officials decided upon further inspection that allowing Mr. Artan to enter the country would be “inadmissible due to vetting concerns.” Later, Andrew Giuliani, the official who leads the White House’s World Cup task force, went further and accused Mr. Artan of having murky ties.
“There were some very terrible people he was talking to,” Mr. Giuliani told the BBC. “We’re not going to allow a soccer tournament to be the opportunity for terrorists to get into the country, or anybody who is actually talking to them.” A spokeswoman for the task force did not respond to a request for comment.
Mr. Artan’s native Somalia has particularly been a regular target for the Trump administration. Earlier this year there was a surge in immigration raids in Minnesota, home to the biggest Somali population in the United States, while Mr. Trump has also invoked unflattering language to describe Somalia, which faces severe travel and visa restrictions.
Mr. Artan said the high-profile nature of his case is likely to have a deeper effect back home. Somalis, he said, could feel further disrespected by Washington and think “our passport, our country name, everything is useless,” if even a decorated World Cup referee can be turned away from the United States.
“This is such a shameful decision by the Trump administration,” said Ilhan Omar, a U.S. representative of Somali descent who has frequently tangled with President Trump. “The World Cup is supposed to be an event that transcends divisions and allows people to come together for the love of the sport.”
A White House spokesman said that Mr. Trump is focused on ensuring that the World Cup is “an incredible experience for all fans and visitors,” but also “the safest and most secure in history.”
But some rights groups, which have opposed Washington’s immigration policies, now fear that the World Cup could be anything but an incredible experience.
“What is happening to players and staff and fans coming to the U.S. for the World Cup is representative of the horrors millions of people in the U.S. are experiencing under this regime,” said Tanya Greene, the U.S. program director for Human Rights Watch. “It’s as if the administration wants to keep the world out of the World Cup.”
Iranian fans have faced added disruption.
The country is on the United States sanctions list, meaning its soccer federation has been barred from selling World Cup tickets to its supporters even if they held valid visas. “FIFA is working closely with the Iranian federation to identify compliant solutions that maximize opportunities for Iranian supporters to attend matches,” a FIFA spokesman said.
The security protocol in the United States has led to uncomfortable scenes for some teams. In the past few days, squads from Senegal and Uzbekistan, countries with sizable Muslim contingents, have undergone the type of rigorous security screening that has not been common at previous tournaments. Uzbekistan’s players were surprised to see security officials waiting for them as they stepped off a bus before a tune up game against the Netherlands in New York. The players were subjected to searches with metal detectors. Fabio Cannavaro, the team’s coach, suggested his team had been singled out for special attention because the Dutch team did not face the same searches. “In the end, the check was only for us,” he said.
Matthew Mpoke Bigg contributed reporting.

