The Trump administration is suing Chicago over what are known as sanctuary laws. The administration claims the nation’s third-largest city “thwarts” federal efforts to enforce immigration laws.

President Donald Trump promised to make immigration enforcement a top priority for his new administration, and in his first few weeks in office, ICE officials have conducted multiple raids around the country, along with opening up Guantanamo Bay as a detention center to hold up to 30,000 people being deported.

The U.S. Department of Justice (DOJ) filed a federal lawsuit on Thursday against the state of Illinois, the city of Chicago, Cook County, and the Cook County Sheriff’s Office, alleging that local laws are obstructing the Trump administration’s efforts to enforce federal immigration policies.