Man is arrested after shots are fired outside a federal building in Chicago that houses two US senators' offices

A security guard raised the alarm about an active shooter near the John C. Chicago police and federal agents swarmed the downtown Loop district and handcuffed the suspect quickly. Officers recovered a firearm and bullet casings, and charges are pending.

Bullet holes were discovered in an office building on the opposite side of the street.

Illinois Democrat senators Dick Durbin and Tammy Duckworth both keep offices inside the tower.

Homeland Security reported no injuries and 'only minor damage to federal property'.