Police escort a man at the scene of a shooting in Waco, Texas, in this handout photo provided by the Waco Police Department on May 17, 2015. Police in Waco, Texas, said on Sunday that gunfire at a sports bar left a number of people dead and others injured while local media reported that nine people had been killed in a fight between biker gangs. [Photo/Agencies]

WACO, Texas - A shootout among rival biker gangs at a popular Texas restaurant left nine people dead, 18 injured and sent panicked patrons and bystanders fleeing for safety, a police spokesman said Sunday.

The violence erupted shortly after noon at a busy shopping center 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 and then spilled into the restaurant where it escalated to include knives and firearms, he said. There were 150 to 200 gang members inside the restaurant at the time.

Police were aware of the meeting in advance, 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. Armed bikers were shot by officers, Swanton said, adding that the actions of law enforcement prevented further deaths. It was not known if any of the nine dead were killed by police officers.

Swanton said that the restaurant's operators were also aware of the meeting in advance and would not cooperate with authorities.

"Apparently the management (of Twin Peaks) wanted them here and so we didn't have any say-so on whether they could be here or not," Swanton said.

Multiple attempts to contact Twin Peaks for comment were not immediately successful.

Three armed gang members were later arrested when they attempted to enter the shooting scene to retaliate against rival members, he said. Officers with numerous law enforcement agencies were seen parked along the service road for I-35 near the city. Swanton said authorities are increasing security in the area to prevent further violence among the gangs.

Swanton declined to identify the gangs but many men wearing vests inscribed with the words "Bandidos" or "Cossacks" were seen in the area.

In addition to local and state police, agents from the FBI and federal Bureau of Alcohol, Tobacco, Firearms and Explosives were also at the scene.