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.

The Trump administration stepped up its legal fight over the president’s crackdown on undocumented immigrants by suing Illinois and Chicago, claiming their “sanctuary” policies prevent local officials from cooperating with federal immigration enforcement.

The lawsuit argues the U.S. Constitution’s Supremacy “prohibits Illinois, Chicago, Cook County, and their officials from obstructing the Federal Government’s ability to enforce laws that Congress has enacted or to take actions entrusted to it by the Constitution.”