A police officer was killed and two others were injured in a Boulder Colorado supermarket shooting on Monday, KDVR-TV reported.
But the number of casualties has not been confirmed by the police, expected to make an official statement.
KDVR-TV could not confirm if there were other deaths or injuries.
But a viral video showed some people lying motionless at the car park.
A shirtless man with blood running down his leg was escorted out of the store in handcuffs by two police officers.
A local hospital confirmed receiving one patient from the active shooting scene.
Officers were initially called to the King Soopers in the southern part of the city of Boulder for reports of a man shot in his vehicle.
When officers arrived the suspect began shooting at them, police said.
Officers had their guns drawn, and some windows at the front of the store were broken.
Authorities over a loudspeaker said the building was surrounded and that “you need to surrender.” T