"This is a mass casualty situation", the department said.
All were taken to area hospitals. "The majority are older adults", Nashville police said on Twitter. "One other victim pistol whipped and at hospital".
The extent of their injuries was not immediately clear.
Nashville Mayor Megan Barry says a shooting at a church is "a awful tragedy for our city".
Police said one of the churchgoers has a gun permit and ran to his auto to retrieve his weapon, after which he confronted the suspect, who then shot himself.More news: Toys R Us Filed for Bankruptcy and People Are Upset
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WKRN's Josh Breslow tweeted this video featuring a woman who lives next door to the church.
This is a developing story, and we will report additional details as they arrive.
A person was taken into police custody, officials told Fox.
"One was in the parking lot that he had shot, in the back".
Samson shot a woman in the parking lot first, police say.
Metro Nashville Police said the scene remained active as of 12:10 p.m. local time and advised people to stay away from the area. Aaron says a churchgoer who confronted the gunman was pistol-whipped by the suspect, who then shot himself.