Nashville, Tenn. (CBS NEWS) — A large explosion in downtown Nashville Friday morning is under investigation by police and federal officials including the FBI and ATF. CBS affiliate WTVF reports the blast was felt across much of Davidson County around 6:30 a.m.

“The explosion was significant, as you can see,” police spokesman Don Aaron said at a briefing Friday morning. “We do believe that the explosion was an intentional act.”

Three people were taken to the hospital for treatment, but officials said the injuries were not believed to be critical.

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