Johnson and three other big-city mayors, all Democrats, will attend the March 5 hearing of the House Oversight and Government Reform Committee, which is investigating how local policies affect enforcement of President Donald Trump’s promise of mass deportations.

Mayor Brandon Johnson will testify before Congress next month as part of a Republican-led House probe into sanctuary cities, his office announced Wednesday.

House Oversight Committee Chairman James Comer (R-KY) sent letters Johnson and the mayors for three other major cities – Boston, Denver, and New York – last week, asking them to testify before the committee and hand over all documents and communications related to their city's sanctuary policies.

Mayor Brandon Johnson’s appearance is likely to represent a flashpoint in the ongoing battle with the GOP-controlled U.S House and the Trump administration, which is attempting to strip self-proclaimed sanctuary cities of all federal funding.

Chicago Mayor Brandon Johnson will be "pressed" for answers about the city's status as a sanctuary city during an upcoming Congressional hearing in Washington, D.C.