The U.S. Justice Department sued the state of Illinois and city of Chicago on Thursday, accusing the Democratic strongholds of unlawfully interfering with Republican President Donald Trump's crackdown on illegal immigration and seeking a court order blocking so-called sanctuary laws.

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.

It appears to be the first Justice Department lawsuit against local officials for allegedly interfering with the Trump administration’s immigration crackdown.

President Donald Trump’s administration went to court Thursday to challenge sanctuary policies in the state of Illinois, Cook County and the city of Chicago that limit the powers of state and local police to assist federal law enforcement on immigration-related matters.

The suit asserts that sanctuary laws in Chicago, Cook County and Illinois have obstructed federal efforts to enforce immigration policy.

Federal officials are asking a judge to bar the Illinois, Chicago, Cook County and the Cook County Sheriff from using local laws that protect migrants to hamper law enforcement.

The Trump administration sued officials in Illinois, Chicago and Cook County on Thursday over policies that limit cooperation with federal immigration enforcement authorities, accusing them of obstructing its immigration crackdown.