BOSTON — Police are responding to reports of gunshots near Boston University.Massachusetts State Police say troopers responded Friday afternoon to a footbridge near campus after receiving reports of shots fired. A Boston University spokesman said he couldn't immediately confirm the report or provide any information.The Boston Globe reported that the shooting involved troopers and Boston University police, who were following a man armed with a knife and who had made threats.Police said the footbridge is near Back Street and Storrow Drive.