The Democratic mayors of Denver, Chicago, Boston, and New York City were grilled for hours over their so-called sanctuary city policies at a Congressional hearing Wednesday as President Donald Trump pushes his aggressive immigration agenda and threatens to punish cities that don’t comply.

The Congressional hearing was part of a federal investigation into so-called "sanctuary cities."Committee Chairman James Comer, a Republican from Kentucky, launched the probe back in January to look into what he described as "the policies of sanctuary jurisdictions and their impact on public safety and federal immigration enforcement.

Democratic mayors of major U.S. cities said Wednesday that Congress and the Trump administration are exaggerating crime committed by immigrants and attacking so-called sanctuary cities simply to score political points,