One teen is hospitalized and more than a dozen others are in jail after a flash mob turned violent in Center City.
As many as 100 teens from three area high schools descended upon The Gallery at Market East Tuesday afternoon, police say.
Security quickly tossed them from the underground mall at 12th and Market Streets when the crowd became rowdy and that's when the situation took a turn for the worse.
Groups made their way up Market Street towards City Hall -- some starting a large snowball fight on the building's grounds while others began fighting on street corners, police said.
Along the way, the teens darted through traffic and knocked strangers to the ground, police said. One witness said the teens were randomly attacking people.
Teens who made their way into Macy's at 13th and Market, damaged parts of the store and stole clothing, eyewitnesses said.
"It was very chaotic," a woman who wished to remain unidentified said. "It was a mob. There were between 40 and 50 kids who tore up Macy's."
Store management reported minor damage.
Once police arrived, most of the teens ran, but authorities arrested 14 high schoolers -- 13 boys and one girl. They were all charged with disorderly conduct and the girl was also charged with aggravated assault, police said.
Several of the students were also charged with narcotics offenses.
Some of the teens attend Simon Gratz High School in North Philadelphia, authorities say. They are working to figure out the other schools involved.
One teen was kicked in the head during one of the brawls and taken to Jefferson University Hospital with head injuries.
Authorities believe the mob may have been organized on Facebook or Twitter. They are investigating the social media angle.
This is not the city's first interaction with teen flash mobs. Thousands of teens descended on South Street in June 2009 -- vandalizing property, beating pedestrians and even stealing a cab.
"We're seeing it more and more as the school year goes on," said Lt. George Ondrejka. "They congregate in Gallery area and when they're moved along, then that's when they run wild."