Democratic lawmakers, five from the Senate and two from the House of Representatives, asked Jamie Dimon, the chief executive of JPMorgan Chase, to list steps the bank is taking to combat discrimination against black customers and employees following a New York Times report about racism at some of the bank’s branches in Arizona.

In two letters to Mr. Dimon on Thursday, copies of which were also sent to regulators, the lawmakers asked whether the bank planned to change its hiring, lending and other practices to ensure it is treating minorities fairly.

The letter from the Senate was signed by Sherrod Brown of Ohio, Robert Menendez of New Jersey, Elizabeth Warren of Massachusetts, Catherine Cortez Masto of Nevada, and Chris Van Hollen of Maryland. The letter from the House was signed by Representatives Emanuel Cleaver II of Missouri and Al Green of Texas.