As part of Fleet Week festivities, there have been military helicopter demonstrations in various city parks, but at today's demo in Cloves Lake Park on Staten Island, things didn't go as planned. As Haz Tweeted, "Osprey helicoper blows down tree and tree branches land on people hanging out!" We hear that 10 people—all civilians—were injured and some were taken to the hospital.

View more news videos at: http://www.nbcnewyork.com/video.

Update: NBC New York has video (above) and WCBS 2 reports, "Marine Corps spokesman Lt. Josh Diddams said the wind generated by the aircraft's propellers broke branches off a nearby tree. The branches were swept into some people on the ground."

One witness told the Staten Island Advance, "People were falling over. I ran away as fast as I could. It looked like a tornado. It was unbelievable." Another said that even garbage cans were blown over.