Protests continue overnight in Chicago, where world leaders are meeting for NATO Summit.
So far, 45 people have been arrested. At least four officers went to However, all injuries are being described as minor.
Friday is the last day of the NATO Summit in Chicago, and the focus is on Afghanistan.
On Monday, NATO leaders are officially signing off on President Obama's plan to pull troops out by the end of 2014.
The President's trying to get NATO leaders to commit to more: a commitment to help Afghanistan after the war is over.