Mayor Rahm Emanuel, under heavy criticism for his handling of a police shooting that resulted in the death of a black teen, gave an emotional apology on Wednesday hours before angry street crowds demanded his resignation.
In a special address to the City Council, the mayor said "I'm sorry" and promised "complete and total reform of the system."
Emanuel's speech was met with applause from the City Council, but protesters said the city's actions do not go far enough.
High-profile killings of black men by mainly white police officers in U.S. cities have prompted a national debate and protests about the use of excessive force by police.
With his voice occasionally breaking, the mayor of the nation's third-largest city reiterated reform steps he has already promised. These include setting up a task force to review police accountability, the appointment of a new head of the agency that investigates police misconduct and searching for a new police superintendent.
Among the systemic problems with police, Emanuel aimed particular criticism at the "code of silence" that keeps police officers from reporting misconduct by fellow officers. He also has criticized the agency that investigates police misconduct for finding almost all police shootings justified.
"We have a trust problem," Emanuel said.
His speech comes after two weeks of protests in Chicago following the release of a 2014 police squad car dashboard video showing police officer Jason Van Dyke shooting 17-year-old Laquan McDonald 16 times. Van Dyke, who is white, was charged with first-degree murder late last month.
Protesters outside City Hall on Wednesday chanted "16 shots and a cover-up," and called for the resignation of Cook County State's Attorney Anita Alvarez, who has been criticized for taking more than a year to charge Van Dyke. One activist was arrested.
Said protester Rosemary Vega: "Today, we're here because we want to see Rahm resign."
Another recently released video shows a man in custody being tasered by police.
The U.S. Justice Department said on Monday it will launch a civil rights investigation into the city's police department, examining its use of force, including deadly force, among other issues.
Also on Wednesday, a federal judge said he would rule by Jan. 14, 2016, on whether to release video in the shooting death of another black teen. The mother of Cedrick Chatman, 17, has sued the city over Chatman's death on Jan. 7, 2013. The city has opposed release of video in the case.