Four students were injured Wednesday after one of them opened fire at a Denver-area high school, the Jefferson County Sheriff's Office said.

Deputies from the Jefferson County Sheriff's Office respond to a shooting at Evergreen High School near Denver on Wednesday. Photo courtesy of the JCSO UPI

Sept. 10 (UPI) -- Four students were injured Wednesday after one of them opened fire at a Denver-area high school, the Jefferson County Sheriff's Office said.

The shooting happened around 12:34 p.m. at Evergreen High School, JCSO spokeswoman Jacki Kelley said in a news briefing.

It wasn't revealed who injured the suspect, but the JCSO said it didn't believe law enforcement fired any bullets. Kelley declined to provide any details such as a name, age or gender about the shooter due to his age.

"I don't know if our suspect is even old enough to drive," she said during the briefing.

Three of the students, including the suspected shooter, were transported to CommonSpirit St. Anthony Hospital in Lakewood, Colo., in critical condition. A fourth student was also taken to the hospital, but the cause of their injuries was unclear.

Police evacuated the high school, transporting the student body of about 900 to a reunification point at Burgen Meadow Elementary School. The JCSO said officials cleared Evergreen High School and there was no further threat to the community.