A shootout among rival motorcycle gangs at a popular Central Texas restaurant left nine bikers dead and 18 injured, and it sent panicked patrons and bystanders fleeing for safety, a police spokesman said Sunday.

The violence erupted shortly after noon at a busy Waco shopping center along Interstate 35 that draws a large lunchtime crowd. Waco police Sgt. W. Patrick Swanton said eight people died at the scene of the shooting at Twin Peaks restaurant and another person died at a hospital.

The nine killed were all members of biker gangs, he said, as were the 18 people who were taken to hospitals with injuries that include stab and gunshot wounds. Some victims are being treated for both, he said.

"This is probably one of the most gruesome crime scenes I've ever seen in my 34 years of law enforcement," Swanton said, later adding, "I was amazed that we didn't have innocent civilians killed or injured."

Dozens of motorcycles were parked in a nearby lot Sunday. Bodies were found in the parking lot of Twin Peaks and in another adjacent lot for a family restaurant.

"Dozens" of suspected gang members have been detained, Swanton said.

Swanton said at least five rival gangs gathered at Twin Peaks for a meeting that he said focused on turf and recruitment, two areas where the groups have often clashed. Preliminary findings indicate a dispute broke out in a bathroom, escalated to include knives and firearms and eventually spilled into the restaurant parking lot, he said. There were 150 to 200 gang members inside the restaurant at the time. Shots were fired inside and outside the restaurant, he said.

Swanton described the interior of the restaurant after a Sunday night walk-through, saying it was littered with bullet casings, knives, a club, bodies and pools of blood. Authorities would be working the rest of the night to process the reams of evidence, he said.

Men in motorcycle jackets could be seen being taken away in police vehicles. Others sat on the ground.

Police were aware of the meeting in advance, Swanton said, and at least 12 Waco officers in addition to state troopers were outside the restaurant, part of a national chain that features scantily clad waitresses, when the fight began.