CHICAGO (CBS) — A police officer shot and wounded an armed former student in an exchange of gunfire outside Dixon High School on Wednesday.

A Dixon police resource officer confronted the gunman around 8 a.m. The suspect fired at the officer, who shot back, injuring the gunman. Dixon is located about 100 miles west of Chicago.

Police Chief Steven Howell said the officer confronted the suspect, a 19-year-old male who had been expelled from school, near the school’s west gym. As the officer pursued the suspect, the offender fired several shots and the officer returned fire. The former student suffered non-life threatening injuries and was taken into custody just west of the school. The officer was not hit.

“I could not be more proud of the police officer. Because of his heroic actions, many lives were saved,” Howell said.

Police did not release the name of the officer, or the suspect, but Gov. Bruce Rauner identified the officer as Mark Dallas in a tweet praising his actions.

Today, we should all be very thankful to school resource officer Mark Dallas for his bravery and quick action to immediately diffuse a dangerous situation at Dixon High School. — Governor Rauner (@GovRauner) May 16, 2018

(Below: Mark Dallas at the office at Dixon High School)

Hey @DixonPolice , a big happy birthday to one of your own! We won't talk about how old he is… pic.twitter.com/NN9YaSilrL — Dixon High School (@dukesduchesses) March 2, 2018

As the high school was placed on lock down, staff and students, used their training and barricaded classroom doors with bookcases and desks, Howell said.

“A lot of things went right today and many things could have gone wrong,” said Dixon mayor Liandro Arellano Jr.

All students were reunited with their families, Howell said.

Authorities did not say what caused the former student to return to the school with a gun.

“No students or staff were injured in the incident. The Dixon High School and all Dixon Public Schools are on lockdown. Dixon Police believe the suspect acted alone and that there is no further threat to the safety of students or staff,” Dixon officials said in a statement on Facebook shortly after the shooting.

Parents were told to go to the baseball fields in Page Park, across the street from Dixon High School, to pick up their children.

Dixon Public Schools officials said high school students were being bused from the Illinois Army National Guard Armory near the school to the baseball fields. Parents must show ID to pick up their kids.