A mother has been charged with riot and disorderly conduct after police said she was seen on video encouraging her daughter to fight another girl in Reading.

Raquel Rosario watched and shouted words of encouragement as her daughter fought a girl near the Intermediate High School on Jan 3, police said.

The girl's sister, Precious Irizarry, also encouraged the fight, police said. She was also charged with riot and disorderly conduct.

The girl's mother and sister, police said, never tried to stop the fight.