Police in the university town of Boulder say they have responded to the incident at the King Soopers super market.
A law enforcement source told ABC News that officers responded to a report of someone being shot in the store’s car park, and were in turn fired upon by a suspect.
“ALERT: Active Shooter at the King Soopers on Table Mesa. AVOID THE AREA. PIO is en-route,” tweeted Boulder Police Department just before 3pm local time.
Jefferson County Sheriff’s Office says they have deployed SWAT to the scene.
A witness told FOX31 that they had seen a man in the car park dressed in tactical gear and carrying an “AR-15 style weapon.”
The King Soopers grocery store on Table Mesa is two miles south of the University of Colorado Boulder campus.