Vice President Mike Pence surprised country music listeners early Thursday morning with a heartfelt message about Sunday's mass shooting in Las Vegas, which occurred during the final night of a three-day country music festival at the Mandalay Bay hotel.

"I can't, for the life of me, imagine what it was like to be there," Pence told Storme Warren, the host of Sirius XM's country music station "The Highway," during a radio interview.

Warren was one of several Sirius XM staffers who were present at the concert late Sunday night and witnessed the harrowing scene after a gunman opened fire on concert-goers from the 32nd floor of a nearby hotel, killing 59 people and injuring hundreds more.

"I spoke to the president last night after he arrived back from Las Vegas and I know he was deeply moved to speak with families of those who were recovering from injuries and to speak with first responders who literally flew into a hail of gunfire," Pence said.

The vice president said he was particularly moved when he learned that concert attendees had sung "God Bless America" in "virtually unanimous chorus" shortly before the 64-year-old gunman began his rampage Sunday night.

"The last time I remember being that moved by that account was when I stood on the steps of the United States Capitol on Sept. 11, 2001 and that same song broke out," Pence recalled.

While several details about the shooter and his motive remain unknown, Pence said the administration is working tirelessly with local and federal law enforcement authorities "to get to the bottom of this."

"We're going to find out what happened here [and] if there were others involved, we're going to hold them to the very strictest account," he said, noting that the shooter's decision to target a country music festival hit close to home for him.

"I literally got a lump in my throat the first time I heard Jason Aldean sing: 'Have you ever been to Indiana?'" Pence said, referring to the Aldean's 2010 hit "Flyover States."

"I know the character of the people who cherish country music. I share their values, their sense of community. And I think we'll come through this stronger than ever before," he told Warren.