CHICAGO (AP) -- Chicago Police Superintendent Garry McCarthy says the protests of the NATO Summit resulted in 45 people being arrested and four officers suffering injuries - one from a stab wound in the leg.

McCarthy talked about the arrests and injuries at a press briefing Sunday night, hours after officers and protesters clashed near McCormick Place, the site of the summit.

No details on the arrests were immediately available, but it appeared from the clashes that played out in front of television cameras that many of those arrested were taken into custody after refusing a police order to disperse.

Several exhausted officers could be seen pouring water over their heads, but it was also not immediately clear if any of the injuries were related to what was a blistering hot day.