Protests in Chicago are expected to grow in the coming days after police on Tuesday released a dashcam video of the shooting of a black teen boy by a white police officer in October 2014, the Associated Press reported Wednesday. Following the video's release, demonstrators blocked streets in Chicago’s downtown late Tuesday.

Prosecutors on Tuesday charged Officer Jason Van Dyke with first-degree murder in the shooting of 17-year-old Laquan McDonald.

Protesters attempted to block traffic on an expressway and some of them also screamed at police officers, the AP reported. About 100 protesters gathered in the area and chanted "16 shots," referring to the number of times Van Dyke shot McDonald.

Aislinn Sol, an organizer for Black Lives Matter in Chicago, reportedly said that about three to four activists were taken into police custody. People are expected to hold more demonstrations, including one at City Hall Wednesday and Michigan Avenue on Friday ahead of Thanksgiving.

"It's powerful we're coming together," Justin Taylor, an 18-year-old University of Iowa student, told the AP. "Things like this happen too often."

Early Wednesday, some activists lamented that Van Dyke had not been charged until a court ordered the police to release the dashcam footages, the Guardian reported.

Given the graphic nature of the dashcam video, city authorities expressed concern about possible riots in Chicago, once the images were made public. Police Chief Garry McCarthy asked protesters to respond peacefully. "We will be intolerant of criminal behavior in Chicago," McCarthy said at a news conference Tuesday.

Chicago Mayor Rahm Emanuel also said Tuesday that the people will "have to make an important judgment about our city and ourselves and go forward." Emanuel added that the incident was a potential "moment of understanding and learning."