India, June 11 -- Visa delays, detentions and entry denials involving players, referees and football officials have sparked controversy ahead of the FIFA World Cup in the United States. Immigration experts and rights groups are questioning whether strict border enforcement could overshadow the tournament.

The debate intensified after Somali referee Omar Artan was denied entry into the US despite reportedly carrying a valid visa and required travel documents. According to Al Jazeera, the 34-year-old official, who was set to become the first Somali referee to officiate at a World Cup, was stopped at Miami airport and later sent back to Istanbul.

The US Department of Homeland Security (DHS) told the outlet that Artan was considered "inadmi...