Police are urging people to stay away from a Walmart in Thornton, Colorado, where a shooting has occurred.
A massive police presence has responded to the Walmart at 9900 Grant Street.
There is no confirmed number of people killed or injured.
"We've got multiple parties down, we're still trying to ascertain what their conditions are," Thornton police officer Victor Avila told Reuters.
The store was "self-evacuated," Avila said, as customers and employees ran away from a volley of gunshots.
Reports of shots fired came shortly before 6:30 p.m. Mountain Time, a police spokesman told local 9NEWS in Denver
Thornton Police Chief Nick Mets tweeted "prayers with the people of Thornton" and emergency responders.
Please be aware....prayers with the people of Thornton and it’s First Responders who are bravely responding to provide aide. https://t.co/xiu01MGfMN
— Chief Nick Metz (@APDChiefMetz) November 2, 2017