Country music duo Big & Rich performed the traditional tune of “God Bless America” at the Route 91 Harvest music festival in Las Vegas just one hour before a gunman opened fire on the crowd, and the moving video has since been shared across social media.

The band’s Big Kenny and John Rich expressed their gratitude to American service members during their Sunday evening concert, on the final night of the three-night country music festival.

“I think we all know that without men and women who are willing to fight for our freedoms in this country, we don’t get to assemble like this and have crazy country music concerts in the middle of Las Vegas, Nevada. It would not happen,” Rich said.

“We are lucky, Big Kenny, that this morning, when our eyes awakened, we found ourselves under the red, white, and blue of the United States,” he added.

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The Grammy-nominated duo also invited veterans and active-duty service members to the stage, as they have been known to do at their concerts.

Just one hour after the group’s performance, suspected gunman Stephen Paddock opened fire on the music festival crowd from the 32nd floor window of his hotel room at the nearby Mandalay Bay Resort and Casino, killing at least 59 people and injuring more than 500 others. Paddock was reported to have killed himself before he could be apprehended by law enforcement officials.

In an interview with Entertainment Tonight following the tragedy, Kenny said the band was “heartbroken,” but vowed to continue with its mission.

“Fear will not overtake us,” he told ET. “We will continue to march forward with our music. I know that all the artists out there, we are all so concerned right now, first and foremost about our fans, but [we] will not let this stop us in any way.”

Right before we walked onstage last night. We are grieving for and with all of the fans right now. We love you❤ pic.twitter.com/tOeK0dyIIl — John Rich (@johnrich) October 3, 2017

“We will go forth every day and shine the light of love as bright as we possibly can against all the darkness and outrageous things like this that might ever come upon our path in life,” he added. “And we will continue to walk in God’s light the best we can.”

Watch a clip from the band’s performance in Las Vegas above.

Follow Daniel Nussbaum on Twitter: @dznussbaum