Chicago 's police chief was ousted on Tuesday following days of unrest over video footage showing the shooting of a black teenager and the filing of murder charges against a white police officer in the young man's death.

Mayor Rahm Emanuel, who had stood by Superintendent Garry McCarthy, announced during a news conference he had asked McCarthy to resign. The mayor said he was creating a new police accountability task force.

The announcements came a week after the officer, Jason Van Dyke, was charged with first-degree murder in the killing of Laquan McDonald, who was shot 16 times. A video of the killing was released on the same day.

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High-profile killings of black men at the hands of mainly white law enforcement officials in U.S. cities over the past two years have prompted demonstrations across the country, and have stoked a national debate on race relations and police tactics.

"The shooting of Laquan McDonald requires more than just words," Emanuel said in a statement earlier on Tuesday.

"It requires that we act; that we take more concrete steps to prevent such abuses in the future, secure the safety and the rights of all Chicagoans, and build stronger bonds of trust between our police and the communities they're sworn to serve."

Emanuel, McCarthy and Cook County State's Attorney Anita Alvarez have faced criticism for taking 13 months to release a video of the 2014 shooting and to charge Van Dyke.

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The video shows Van Dyke gunning down McDonald, 17, in the middle of a street on Oct. 20, 2014, as McDonald was walking away from police who had confronted him. Van Dyke, 37, was released from jail on Monday after posting bond on a $1.5 million bail.

Protests followed the charging and arrest of Van Dyke and the release of the video on Nov. 24. In a protest on Monday, the president of the National Association for the Advancement of Colored People, Cornell William Brooks, was one of several protesters arrested, the organization said.

Emanuel said the new task force, which will be advised by former Massachusetts Governor and  Chicago  native Deval Patrick, will review the system of accountability, oversight and training in the police department.

The five-member panel will recommend reforms to improve independent oversight of police misconduct, ensure officers with repeated complaints are evaluated and establish a process for release of videos of police-involved incidents, Emanuel said. Its recommendations will be presented to the mayor and city council by March 31, 2016.