U.S. attorneys’ offices were told to investigate any official who defies federal immigration enforcement efforts and consider prosecuting them.

The Justice Department memo issued Wednesday threatens prosecution of state or local officials for “resisting, obstructing, and otherwise failing to comply with lawful immigration-related commands and requests.

The mayor El Paso and his chief of police on Wednesday said they will honor calls from federal law enforcement partners in need of assistance but will not volunteer municipal officers for immigration enforcement.

A memo asserts that state and local officials are bound to cooperate and could face criminal prosecution or civil penalties if they fail to comply.