NILES — The last day of classes at Niles High School ended with a fight about 1 p.m. Thursday.

Four students were arrested in connection with the incident, which began as an altercation between two students, police said.

One of the teens had a single-edged razor blade that he allegedly used to inflict a 1-inch cut on another teen’s head, police said. The injured teen did not need medical treatment.

The teen with the razor blade faces an assault with a deadly weapon charge while the others were arrested on assault and battery and disturbing the peace charges, police said. All were between 15 and 16 and were released to their parents pending disposition from juvenile court.

Niles Superintendent Doug Law said the altercation began by the doors to the main parking lot during the second half of lunch. Security personnel broke up the fight.

Law said that once the police investigation is complete, the school will follow its disciplinary procedures regarding the incident. Any school discipline the students may face will carry over into next year.