Department of Homeland Security (DHS) Secretary Markwayne Mullin has warned that sanctuary cities could face significant consequences if they refuse to enforce federal immigration laws. Mullin suggested that cities unwilling to cooperate with federal authorities might lose access to critical federal functions, such as processing international flights. He also suggested that federal lawmakers might examine sanctuary city policies. The Department of Justice has created a specialized unit to target sanctuary jurisdictions whose local laws limit cooperation with federal immigration authorities. Last year, a House GOP probe investigated several major sanctuary cities for their policies that restrict cooperation with Immigration and Customs Enforcement (ICE).