Chciago Tribune staff, Associated Press

Officials say a police officer working at Dixon High School shot and wounded a former student who fired a gun at him Wednesday.

The incident began near the school’s west gymnasium about 8 a.m., according to officials speaking at a late-morning news conference.

Earlier in the day, City Manager Danny Langloss said students were gathered at the gym for graduation practice.

Dixon police Chief Steven Howell said the suspect, a 19-year-old former student, “fired several shots near the west gym.”

The school resource officer confronted the suspect, who then fled from the school with the officer in pursuit, Howell said. During the pursuit, the suspect fired several shots at the officer but did not strike him.

The officer returned fire and struck the suspect, who was then taken into custody just west of the school, Howell said. He was taken to a hospital with non-life-threatening injuries. No one else was injured.

An earlier account said the gunfire exchange took place in the gym.

Sauk Valley Media said the sheriff identified the officer as school resource Officer Mark Dallas.

Howell praised the officer for saving lives. Dixon Mayor Liandro Arellanno Jr. also praised the officer’s response.

“From the angle I’m looking at right now, at lot of things went right today when a great many of them could have (gone) wrong,” he said. “Things could have gone much worse.”

Authorities have not provided the gunman’s name.

Authorities say students did exactly as they were trained to do in such situations. Officials said they were pleased to discover that students had barricaded themselves into classrooms by blocking doorways with chairs, desks and other furniture.

Police have not said why the former student came to the school.

According to the city of Dixon website, the school resource officer position was started by the Dixon Police Department in 2000 to help prevent school violence.

Check back for updates.