Homeland Security Secretary Markwayne Mullin on Monday questioned whether cities with international airports that do not cooperate with federal immigration enforcement should continue to receive full customs processing services.

Speaking about sanctuary cities, Mullin asked whether such jurisdictions should be allowed to process customs operations at their airports. "If they're a sanctuary city, should they really be processing customs into — into their city?" Mullin said, according to reports.

The comments suggest the Department of Homeland Security may consider restrictions on customs services at major international airports in sanctuary cities. Such airports include facilities like Los Angeles International Airport (LAX) and John F. Kennedy International Airport (JFK) in New York.

Sanctuary cities typically limit cooperation with federal immigration authorities and may restrict local law enforcement from detaining individuals based solely on immigration violations. The designation has been a source of ongoing tension between federal and local governments.

Multin was recently confirmed by the Senate to lead the Department of Homeland Security. The agency oversees customs and border protection services at international airports across the United States.

Any potential changes to customs processing arrangements would likely face legal challenges and could significantly impact international travel and commerce at affected airports.