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LAS VEGAS — The lights were still dazzling and gamblers still placed their wagers, but there seemed to be a pall over the party-central Las Vegas Strip on Monday night, a day after a gunman opened fire on a crowd of concertgoers and killed at least 59 people in the deadliest mass shooting in modern U.S. history.

"The vibe — it's different," Duran DeGonzales, 28, a Las Vegas resident, said after snapping a selfie in front of the Bellagio Resort & Casino. "It doesn't feel sad. It feels, I don't know, lonely."

One could hear a pin drop on the closed section of Las Vegas Boulevard near the scene of Sunday night's shooting, in which a gunman opened fire from the 32nd-floor window of Mandalay Bay Resort and Casino before apparently killing himself. At least 500 people were injured, and police haven't determined a motive.

Farther up the Strip, visitors strolled along the sidewalk, drinking and taking photos. But signs of the shooting were everywhere. The digital display at Mandalay Bay showed a number that people could call to locate loved ones. The Paris Las Vegas Hotel & Casino had a pink heart with the Strip skyline and the hashtag #Vegasstrong.

A screen outside the Cosmopolitan of Las Vegas showed black text on a white background that read: "Our hearts are with the victims, their loved ones, and the Las Vegas community." And while crowds gathered along the Bellagio's lake for its fountain display, the fountains were turned off for the night.

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"Even this morning at the Bellagio, and normally, there are all these sounds," said Sean Palas, 36, of St. Louis, who was on his honeymoon with his wife, Becca. The card dealers weren't at their tables but instead gathered in a group, talking, he said.

"It's like everything had stood still," Palas said.

On a pedestrian bridge north of the closed-off section of Las Vegas Boulevard, overlooking a largely empty thoroughfare with police cars' flashing lights in the distance, some visitors brought flowers or small candles.

Scott Stone, 53, who moved to Las Vegas almost a year and a half ago, contemplated the scene. "You just think, how many hours ago, it was just mayhem," he said. "When you go inside these casinos, like Luxor — it's like a normal day."

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Staff at some casinos said security had been increased after the shooting. Police seemed to have a heavier-than-normal presence on the Strip, some said.

"Monday's usually real busy with Monday night football," said Bill Albright, 53, who, along with his wife, Joni, lives in Vegas and usually visits the Strip every Monday and Tuesday. "You can see that the volume of people is way down."

MGM Grand Las Vegas canceled its shows for Monday. The Palases, who were supposed to have seen David Copperfield, called the disruption understandable. They had planned to travel down near Mandalay Bay on Sunday night but were too tired and called it an early night.

"And then we wake up, and I had, like, 10 messages," Sean Palas said. "We thought something happened after the reception," like an accident.

Other frequent visitors said they didn't notice much of a change. Outside a store north of the New York-New York Hotel and Casino, signs advertised "ultimate outdoor machine gun adventure" next to advertisements for Grand Canyon helicopter tours.

Don Richards, who was with DeGonzales, said his behavior wouldn't change. "I'm not going to be scared in my own city," he said.

With Las Vegas' revolving cast of visitors, the tourist scene will likely return to normal soon, said Sean Cohens, a DJ at Mandalay Bay who wasn't working Sunday night.

"From a local's point of view, things will never be the same," said Cohens, 35, who was born in Los Angeles and raised in Las Vegas.

"I don't think the city will ever be normal after this," he said. "This is surreal, man. Surreal."