Hundreds of protesters gathered Sunday night outside of the museum where first lady Michelle Obama was hosting a dinner for spouses of NATO leaders. At least 100 Chicago police officers are on the scene. They're in riot gear, wearing helmets and holding batons.
Their gathering follows an impromptu protest through downtown. At one point a few police officers with shields tackled a protester.
Earlier in the day, it was a tense scene following a march near McCormick Place where NATO leaders met Sunday. Police officers and protesters were in a standoff and there were a few injuries and arrests as officers tried to clear the scene.