CHICAGO, Aug. 25 (Xinhua) -- The unrest following police shooting of a black man in Kenosha, Wisconsin on Sunday evening continued into Monday, when crowds tried to cram into the Public Safety Building for a news conference, knocking a door off its hinges.

Riot police tried to disperse the crowds with tear gas and pepper spray. Meanwhile, Kenosha Mayor John Antaramian confirmed more than 100 Wisconsin National Guard members had been deployed in Kenosha by late Monday.

A video posted on social media shows 29-year-old Jacob Blake walked to a grey van followed by two police officers with weapons drawn. As Blake opened the door to get in, an officer grabbed Blake's shirt to hold him still, and shot him at close range in the back at least seven times.

Blake was in stable condition Monday after surgery, his father said in a social media video.

Protests erupted immediately following the shooting on Sunday evening. At least three garbage trucks were burned out and windows were shattered at several businesses. A police officer was injured by a brick, said the mayor at the news conference on Monday.

In a statement released on Monday, Democratic presidential nominee and former Vice President Joe Biden said the shots "pierce the soul of our nation."

"Equal justice has not been real for Black Americans and so many others. We are at an inflection point. We must dismantle systemic racism," Biden added.

The Division of Criminal Investigation under the Wisconsin Department of Justice is investigating the case. "We understand that there is a need for this investigation to move swiftly," Wisconsin Attorney General Josh Kaul said at the news conference. The division aims to provide a report on the incident to the prosecutor within 30 days.

The Blake family has retained civil rights attorney Benjamin Crump to represent them. Crump also represented George Floyd's family after Floyd was killed by police brutality in May in Minneapolis in the U.S. state of Minnesota.