A 20-year-old man was arrested for allegedly flying a drone within feet of a Philadelphia police helicopter Wednesday evening in Center City.

Joseph Roselli is facing charges of aggravated assault, causing catastrophe, simple assault and recklessly endangering another person, police said Thursday.

The drone was first seen around 6 p.m. over the area of 18th and Walnut Streets where an anti-Trump protest was engaged in a faceoff with police, said Chief Inspector Scott Small. The drone "came within feet" of the helicopter, which was monitoring the protest below.

That close contact between the drone and helicopter led to the assault charges, said Officer Christine O'Brien, a police spokeswoman. The drone nearly hit the helicopter's windshield, she said.

Police tracked the drone to a building at 19th and Chestnut Streets and arrested the operator, Small said. - Robert Moran