The suit was filed in the Eastern District of New York. The department argued the city's sanctuary policies amount to an "intentional effort" to obstruct federal immigration enforcement and should be declared unlawful under the Constitution's Supremacy Clause.

The action comes days after an off-duty Customs and Border Protection officer was shot in the face during an ambush robbery attempt.

New York City is among Democratic-led sanctuary cities in the US that have pledged to withhold assistance to federal authorities seeking to deport illegal immigrants. The lawsuit comes despite Adams’s calls for changing the city’s sanctuary laws to allow local law enforcement to notify federal immigration agents when illegal immigrants are arrested for violent crimes.