By Lisa Respers France, CNN

(CNN) -- Country music star Jason Aldean returned to Las Vegas a week after a deadly mass shooting to visit with some of the victims.

The University Medical Center of Southern Nevada posted to Facebook a photo of Aldean outside of its trauma center Sunday with a message of gratitude to the singer.

"Our extreme gratitude to Country Music Star Jason Aldean for visiting UMC today," the post says. "Jason spent time with our patients who were critically injured during the Las Vegas shooting. His visit helped heal hearts and cheer those who were wounded in this tragedy. #vegasstrong."

Aldean and his band had been performing during the Route 91 Harvest Festival last Sunday when Stephen Paddock opened fire from his hotel room above the country music event, killing at least 58 people and injuring nearly 500 in the worst mass shooting in modern American history.

Aldean's wife, Brittany, posted about their return on her Instagram page, saying it "Feels surreal being back in Vegas today."

"Visiting some of the strongest people we have ever met... fighting the toughest battle of them all... for their lives," read the caption on a photo showing her and her husband with their backs to the camera. "You have helped us try to begin the healing process by seeing the strength each one of you have."

"Thank you for today," she added. "We will never forget. #vegasstrong."

The trip came hours after Aldean opened "Saturday Night Live" singing a cover of the late Tom Petty's hit "I Won't Back Down" in tribute to the Vegas victims.

"We hurt for you and we hurt with you, but you can be sure that we're gonna walk through these tough times together every step of the way," Aldean said on "SNL."

Petty died last week after suffering cardiac arrest in his Malibu home.