A girl was stabbed by her classmate at Zion-Benton Township High School Friday morning, police said.

Zion police said two 17-year-old girls got into a fight and one stabbed the other. The victim suffered critical injuries, police said, and taken to a hospital for treatment. 

Police said the other girl fled the school's campus after the stabbing, but the school's resource officer was able to give police "critical information" and they took her into custody a short time later. 

School District 126 officials sent a note out to parents, writing, "an isolated incident occurred on campus earlier today. Out of an abundance of caution, the school has been placed on code yellow."

Code yellow typically means the school has locked its doors and restricted outside activities. It is one step down from a code red or lockdown.

District officials said there was no threat to students and staff, and that the school is "following established safety protocols."

Further details about what caused the fight, and any pending charges was not immediately available.