Carrie Underwood Thanks Nashville First Responders Following Christmas Day Explosion

What is usually a quiet morning in Nashville, Tennessee, residents of Music City were shook on Christmas morning after an intentional bomb was set off on second avenue right off the city's famous Broadway strip. As a result, the wireless network AT&T was hit causing users in-state and throughout surrounding states to lose service and wifi. Several celebrities have sent their love and thoughts to those affected by the terrifying explosion, including country music star Carrie Underwood.

"Merry Christmas everyone! And a huge thank you to all the brave first responders in Nashville this morning," she tweeted. At least three people were injured in the explosion and according to Metro Nashville Police Department, the blast, which occurred around 6:30 a.m. local time, is being labeled as "intentional." The MNPD, FBI and ATF, along with other agencies are involved in the investigation as law enforcement desperately try and find who's responsible.

Nashville's Mayor, John Cooper, announced a city curfew via Instagram, writing in a statement, "I have signed Executive Order 12 to issue a state of civil emergency proclaimed within the area bounded by James Robertson Parkway, 4th Ave north, Broadway and the Cumberland River. A curfew will start at 4:30pm, Friday Dec 25, and be lifted Sunday, December 27, at 4:30pm. Executive Order 12 also brings Metro resources to bear in response and relief efforts."

Just a day after the explosion, police already have persons of interest. "CBS News has learned that [police] have a person of interest or persons of interest in connection with the [explosion] that rocked [Nashville] on [Christmas Day]" CBS' Chief Justice and Homeland Security Correspondent Jeff Pegues tweeted on Saturday morning. A law enforcement source told the news outlet that a person of interest "has been identified" in connection to the explosion. That person is connected to the RV that broadcasted an evacuation notice, as well as a bomb warning, before exploding.

At least three people were wounded in the attack and were transported to area hospitals. They suffered non-life-threatening injuries. Metro Nashville PD Police Chief John Drake also told reporters that investigators found tissue near the blast site. He did not say whether the tissue originated near the RV that exploded. He only said that the authorities believed it to be human.