A giant balloon in the Macy's Thanksgiving Day Parade snagged a street light and caused part of it to fall, injuring a woman and a child.

The accident happened in Times Square on Thursday near the end of the parade when the tethers on the "M&M's Chocolate Candies" balloon became entangled on the head of the street lamp and knocked it off.

"It happened so fast," parade spectator Karim Simmons said. "It dropped like a rock."

The accident marred the holiday celebration, but the injuries were less serious than those incurred in a parade accident eight years ago. A balloon in 1997 knocked over a light post, critically injuring a woman and prompting changes in parade rules.

Police said the woman, 26, and the girl, 11, who were hit Thursday were sisters from Albany. The girl was treated for minor scrapes on the side of her head. The woman, who was in a wheelchair, needed six stitches on the back of her head. Both were released from a hospital by late afternoon.

"We should be thankful none were more seriously hurt," Mayor Michael R. Bloomberg said.

The crew handling the balloon was apparently trying to correct its course after a gust when it became entangled with the light, Bloomberg said. The National Weather Service said the wind speed in Central Park at 11 a.m. was 10 mph, with gusts up to 21 mph.