The King Soopers is located at 3600 Table Mesa Drive, the Boulder Police Department (BPD) said.
A shooting was first reported just before 3 p.m.
Police have not yet given any information regarding a number of victims or a suspect.
9NEWS’ Marc Sallinger is outside the store and said hundreds of law enforcement vehicles are in the area.
He has also observed some people being ushered out of the store and huddling in the parking lot, as officers bring them blankets.
Law enforcement from multiple local agencies are on the scene.
People are asked to avoid the area, as this remains an active situation. In a tweet, Boulder Police asked that people not broadcast any tactical information from the scene on social media.
This is a breaking news situation, this story will be updated as more information is released.
Local leaders respond
Local leaders in Colorado, including Gov. Jared Polis and Congressman Joe Neguse who are both from Boulder, have shared statements online.
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