At least four people were dead and 11 others were being treated after a "mass shooting" on Sunday in downtown Jacksonville, Fla., during a gaming event at a popular shopping center filled with bars and restaurants, law enforcement sources told Fox News on Sunday.

The gunfire was heard around 1 p.m ET at a video gaming event held at The Jacksonville Landing, Madden NFL Championship Series. The shooting, according to the Jacksonville Sheriff's Office, happened "inside one of the restaurants in the Landing."
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