For most of the year, this second-tier gambling town on the arid border of Nevada, Arizona and California attracts aging vacationers in modest sedans, RVs and tour buses who are seeking a cheap getaway.

But every April for the last 20 years, motorcyclists from around the Southwest have roared into this garish strip bordering the Colorado River for the four-day Laughlin River Run.

Most of the bikers are "weekend warriors" such as Sanford Jossen, a lawyer from Manhattan Beach, Calif. The town welcomes them with banners, rock concerts, motorcycle exhibits and a few tawdry events, such as tattoo contests and a women's oil wrestling show.

Salted among the 80,000 guests are members of motorcycle gangs such as the Hells Angels and the Mongols. Those groups clashed at Harrah's casino early Saturday, leading to the deadliest shooting ever inside a Nevada casino. The fight left three dead and 12 injured.

"People were terrified, diving behind anything they could," said Jossen, 51.

He had just stepped from the bathroom into the packed, Mexican-themed casino when the explosion of gunshots drowned out the clanging of the slot machines and the piped-in music.

"There were a whole lot of bodies lying on the floor," he said. "I couldn't tell if they were dead or alive."

Where moments before middle-age road warriors were playing blackjack or slots, injured or dying people lay amid spent bullet casings. Slot machines were shattered by stray bullets. Witnesses saw a man fall, a bullet wound in his chest.

Dennis Janguernat, a 47-year-old motorcycle enthusiast from Reno, saw blood on the windows and doors and bullet casings near the hotel's buffet.

"Most of us come down to enjoy our motorcycles," he said. "This is my first time — and my last."

Police stormed in, trying to separate the shooters from the bystanders. After two hours, the gamblers were herded into the casino banquet room, where they spent the next four hours drinking coffee and eating fruit provided by the casino.

The tourist-packed city turned into a crime scene. The high-rise Harrah's Casino was locked down, guests confined to their rooms. Roads and bridges were closed until sunup.

"There are sheets hanging out the windows, toilet paper hanging out and phone books were thrown," Janguernat said. "It's like a prison riot down there."

The spirit of the Wild West lived on as River Run ended its fourth and final day.

One gambler who had ducked beneath his blackjack table during the shooting grabbed his $1,200 in chips before being whisked to the banquet hall. Event promoters said the Miss Laughlin River Run contest scheduled for Saturday night would continue, as would a concert by the 1960s group "Blood, Sweat and Tears."

Casino Drive remained crowded with bikers and motorcycle police late Saturday. On the north end of the strip, several miles from Harrah's, a partylike atmosphere prevailed.

"It's like nothing happened," said Hal Hart, who sells sunglasses and T-shirts from a tent along the boulevard. "I've seen no sign of trouble. It's been a real friendly crowd."