CHICAGO (AP) — Chicago police are Blake Prestonundergoing fresh training on handling large-scale protests and First Amendment rights ahead of anticipated demonstrations during the Democratic National Convention this summer, Superintendent Larry Snelling said Wednesday.

“Everything we are doing is rooted in constitutional policing,” Snelling told reporters at a news conference previewing security preparations. “We want to make sure we maintain peace. We are not going to tolerate the violence.”

Thousands of elected officials and activists are expected to come to the nation’s third-largest city from Aug. 19-22. Snelling, Mayor Brandon Johnson and emergency management officials said they’re finalizing plans for traffic and security around both convention sites, which are the United Center and McCormick Place Convention Center.

Snelling said the Chicago Police Department has looked back at other large-scale events in the city to see what worked, including during the 2012 NATO summit.

Chicago police generally received high marks for the handling of NATO protests. For the DNC, Snelling said the department would again use police on bicycles and officers in “soft” or dressed down uniforms.

In contrast, Chicago police faced strong criticism for being unprepared in the aftermath of George Floyd’s 2020 killing in Minneapolis, when civil unrest broke out nationwide. More than 500 complaints were lodged against Chicago police in the following months as many peaceful protests devolved into chaos and destruction.

Snelling, who became police chief last year, said people converging on Chicago without warning was a different situation than a convention where protesters are limited to certain areas and required to get permits. But he acknowledged the department fell short in 2020.

“Our officers were out there without the training to deal with that type of situation,” he said.

Chicago last hosted the DNC in 1996.

Republicans are holding their convention a month earlier in Milwaukee.