Somali referee Omar Artan was detained for 11 hours at Miami International Airport and denied entry to the tournament. A US official claimed he had links to terrorist organisations.
Iraqi striker Aymen Hussein was detained and questioned for several hours at Chicago airport before being allowed entry.
Iran's national team was forced to relocate its base to Mexico. All Iranian supporter tickets were cancelled by US authorities, and delegation members were denied visas.
FIFA president Gianni Infantino called the Artan incident "unfortunate" and advised people to "chill, relax." At a press conference on the eve of the tournament opening, Infantino defended US President Donald Trump, stating that a World Cup largely hosted in the US would have been "impossible" without him.
Iran's visa and ticket issues may create psychological disadvantage before their matches: absence of home support and organizational disruption increase likelihood of lower totals in Iran's games and favor their opponents.