Heavy metal fencing was brought in overnight by the truckload and set up across the street from McCormick Place, where world leaders will convene Sunday and Monday.
The extra protection came hours after residents in the nearby Bridgeport neighborhood clashed with roving protesters. The demonstrators, many of whom covered their faces with bandanas, walked through the streets shouting obscenities about law enforcement.
At times they were met with officers creating barricades with their bodies and bicycles. Without being able to pass, demonstrators took to alleys, knocking over trash bins and pushing large trash containers into the streets.
The march escalated with a shouting match between protesters and area residents when the march arrived at the Deering District station near West 31st and South Halsted streets.