(CNN) -- Authorities Saturday were investigating reports of an active shooter at a shopping mall in Columbia, Maryland.
There was no word on injuries but local scanner reports had authorities requesting multiple mass casualty units.
Images on Twitter reportedly from the scene showed mall employees hiding in a stock room.
The Howard County Fire Department on Twitter reported an active shooter situation at the Columbia Mall.
Both the Howard County police and fire departments were on the scene.
The fire department via Twitter advised people to avoid the area. CNN was first alerted to this story on Twitter.
Editor's note: According to Howard County Police's Twitter account three people are confirmed dead.
Update (12:32pm ET): The Howard County Police Department has tweeted the following, "One deceased subject located near gun and ammunition. ID unknown."
Update (12:41pm ET): The Howard County Police Department tweets, "One subject dead is suspected shooter. No information about other victims yet."
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