At least three people are in critical condition after a shooting involving an “active assailant” at Evergreen High School in Jefferson County, Colorado, officials said Wednesday afternoon.

The county’s 911 dispatch center posted at 12:40 p.m. about an assailant near the high school and described it as an “active scene” in a post on social media at 12:40 p.m.

Three people from the high school are being treated at CommonSpirit St. Anthony Hospital in Lakewood, Colorado, and are in critical condition, spokesperson Lindsay Radford said.

Jefferson County Sheriff’s Office officials confirmed at least two students were shot and were being taken to the hospital.

Parents and guardians should not go to the high school because of ongoing police activity. A reunification area is being set up at Wilmot Elementary School, 5124 S. Hatch Drive.

Jeffco Public Schools officials said the district does not have any additional information from law enforcement about the shooting.

This is a developing story and will be updated.