US President Donald Trump speaks next to first lady Melania Trump after meeting with police at the Las Vegas Metropolitan Police Department in the wake of the mass shooting in Las Vegas, Nevada, October 4, 2017. [Photo/Agencies]

Trump and first lady Melania traveled to the University Medical Center of Southern Nevada on a private visit to see patients and medical professionals there.

Surrounded by doctors and nurses, the president praised the medical teams who treated dozens of patients on Sunday night.

University Medical Center confirmed about 50 people were admitted to the hospital located in Las Vegas after Stephen Paddock, a 64-year-old gambler and real estate investor, opened fire Sunday night on an outdoor music festival on Las Vegas Strip.

"What I saw today is just an incredible tribute to professionalism," Trump said.

The Trumps also met with police, first responders to the shooting spree and volunteers who helped prevent an even greater loss of life when Paddock rained bullets from the 32nd floor of the Mandalay Bay hotel into a crowd of more than 22,000 people attending Route 91 Harvest Country Music Festival.

"The president of the United State is the highest ranking official of the country, when that person take his time to come down here to see the officers, thank for what they did, it's an uplifting to all of us officers," Steven Grammas, the president of the Las Vegas Police Protective Association (LVPPA), told Xinhua.

A day after his visit to hurricane-ravaged Puerto Rico, Trump's visit to Las Vegas on Wednesday is his second trip in two days aimed at comforting victims of tragedy.

Days after the mass shooting, Grammas doesn't "think it's late." "Bring him here early would have caused problems," he added. "We are still dealing with the whole lockdown there."

As the president departed the White House, Trump told reporters, "It's a very, very sad day for me, personally."

The worst mass shooting in modern U.S. history has renewed vehement discussion in the country about the curb of gun violence.

According to the non-profit organization Gun Violence Archive, the mass shooting in Las Vegas late Sunday night was the 273rd gun shooting in the United States in the 275 days of 2017 so far.

On Tuesday, when asked whether it was time to debate gun control measures, Trump responded, "Perhaps that will come. But that's now for now."

"Don't be sorry. No one could really prevent it other than better security," local resident Jade Marie Fliegman, who was locked down in a nearby Casino in the massacre, told Xinhua after the shooting.

"I worry about a lot the safety in America, because it feels like it has happened more and more through the past few years," Fliegman said.