Democratic mayors of four major 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,

Mayor Brandon Johnson testified in front of the U.S. House Oversight Committee, staunchly defending the city of Chicago and its immigrant sanctuary policies. Johnson’s opening statement alluded to the misrepresentation of sanctuary cities.

Johnson and the other mayors defended their immigration policies, saying they have an obligation to protect everyone living in their cities, regardless of their immigration status.

Republican lawmakers on Capitol Hill are taking aim at the Democratic mayors of New York City, Boston, Denver and Chicago over their so-called sanctuary city policies on immigration.

So-called sanctuary city policies are a “public nightmare” that make American cities more dangerous, Rep. James Comer said Wednesday.

As Boston Mayor Michelle Wu departed Capitol Hill on Wednesday, her challenger in this year’s mayoral race, Josh Kraft, said he supported the immigration policy that Wu had defended to congressional Republicans.

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.

Boston Mayor Michelle Wu testified during a more than five-hour House Committee on Oversight and Government Reform hearing Wednesday on the city's immigration policy.