During a Saturday evening march headed west on Harrison Street over the south branch of the Chicago River, a second became kettled at State and Congress, while the third gathered at 175 N. Desplaines, and proceeded south towards the others. After converging near Madison and Jefferson, the larger gathering moved north, then east, to turn south onto State Street, when double lines of police on foot and bicycles again met, stopped, and kettled the crowd of approximately 1,500, arresting several, while using batons to beat several more. The crowd worked its way south on State Street, and as it neared Taylor, it was again hemmed in, Around ten people in the assembly were beaten.
In the video below, livestream captured a police van that drove through a crowd of protesters, and as you'll see there is one man who ends up on the front of the van attempting to hang on to avoid falling under the wheels and being crushed.
There is an account of this incident in a local news report, and this is being blamed by police as well as the reporter as the police coming under assault from the protesters. There is also a video at this link from that local report, and a Chicago police official is interviewed. Note a woman standing behind the official and her reaction to his account of the events. This video also does show as noted by the reporter, at least two persons in black coming up beside the police van with something in their hands (The reporter says sharp objects) allegedly used to "slice the tires" of the van. This would normally be assumed to be "black bloc" protesters, however the Twitter feeds had mentions of police being overheard on scanners discussing changing clothing to look like black bloc to join the NATO protesters. Twitter reports are generally unconfirmed, but worth mentioning when there are many tweeting similar statements, especially with as much chaos as there was on Saturday.
The local reporter speaking to that Chicago police official did ask if police vehicles accelerating when caught in large groups of people was what they should normally do, and the official seemed rather caught off guard when he found out that the news crew had the incident on video. He responded that the video was something they (CPD) would need to take a look at.
No word yet regarding injuries resulting from the many police actions other than the man who is caught up by the police van in the following video being hospitalized, and by Twitter accounts he is also under arrest with friends being denied any visitation by police.