Police say 10 students at a Stamford high school face charges after a food fight that turned into a riot and ended with injuries to a teacher and a school resource officer.

Stamford police said Tuesday that the Westhill High School students, who are between 15 and 17, are charged with first-degree rioting, breach of peace, reckless endangerment and assault on a police officer.

School officials said Friday's food fight had been in the planning for days and developed in a courtyard next to the cafeteria.

Police said the resource officer was struck in the head by a full soda can while the teacher was "trampled by a mass of students."

Stamford Superintendent Earl Kim called the incident "ugly and disappointing."