A bloody shootout Sunday in the parking lot of a racy sports bar here came amid rising tensions between rival Texas biker gangs, the Bandidos and the Cossacks, who authorities say opened fire on each other before turning their guns on police.

The lunchtime fight started in a restroom at the Twin Peaks sports bar on Interstate 35 in south Waco. But it quickly escalated as the motorcyclists began wielding knives, brass knuckles, chains and, ultimately, guns. Up to 100 shots were fired outside the restaurant, located in a small retail center, authorities said, just as families were heading home from church services.

When it was over, at least nine bikers were dead, more were injured, and 170 people had been arrested and charged with engaging in organized crime in connection to capital murder — an offense that carries the death penalty. They were each being held Monday on $1 million bond, a sign that local officials were taking no chances of freeing the rival gangs to take up the battle once again.

“Texas will not stand for the type of lawlessness we witnessed in Waco yesterday,” Gov. Greg Abbott (R) said in a statement.

Descriptions of the melee evoked a war zone rather than a chain restaurant that advertises itself as family-friendly and features $2 “girl sized” and $3 “man sized” draft beers. After the shootout, the parking lot was riddled with bodies, blood and bullet casings.

“It was chaos,” said a man who works at a Cabela’s Outpost outdoors store across the parking lot from Twin Peaks. He would identify himself only as J.R., out of fear, he said, of becoming a target. “People were screaming and going crazy. Most of it seemed to be in the parking lot, and it was over very quickly.”

Sgt. W. Patrick Swanton, a Waco police spokesman, said no police officers or other bystanders, remarkably, were injured in the shootout. But the bodies of the bikers, both the dead and the injured, were strewn throughout the restaurant and the parking lot.

“We had wounded inside, we had people stabbed, we had people shot, and we had people beat,” Swanton said.

On Monday, authorities continued to pore over the scene. Twin Peaks — which features a mountain theme, including waitresses in scanty “Lumber Jill” costumes — was closed, as were many of the surrounding businesses. More than 100 motorcycles and dozens of other vehicles remained in the parking lot as detectives worked behind yellow police tape.

The local Harley-Davidson dealership, about half a mile down the road, was also shuttered, apparently to eliminate a potential gathering place for gang members.

On Sunday, hundreds of bikers from as many as five clubs had assembled at Twin Peaks, where the Texas Confederation of Clubs and Independents, a bikers’ rights association, had scheduled a regional meeting, according to the group’s Web site. Regional meetings occur periodically throughout the year, at locations including sports bars and Harley-Davidson dealerships.

Motorcycles were a common sight at Twin Peaks, said Saul Cornejo Bravo, 19, a server who was working Sunday at a Mexican restaurant next door. “But not that many, especially on a Sunday afternoon,” he said. “Usually I see them there later at night.”

There were other signs that this meeting would be different. According to bikers in the Waco region and experts on motor­cycle-gang culture, a feud had been brewing for months between the Bandidos, one of the nation’s oldest biker gangs, and the smaller Cossacks, who have been challenging the Bandidos’ dominance in the Lone Star State — perhaps with the backing of the Bandidos’ hated rivals, the Hells Angels.

“My perception is that the Cossacks have been flirting, if you will, with Hells Angels,” said Steve Cook, a Kansas City-area police officer who has worked undercover in gangs associated with the Bandidos. “If I’m a Bandido, my immediate reaction is: ‘These guys are going to try to make a move and bring an international gang into our state, which is going to cause a war.’ ”

Of more than 300 outlaw motorcycle gangs in the United States, the Justice Department lists both the Bandidos and the Hells Angels among eight that “pose a serious national domestic threat” because they engage in a host of violent criminal activities, including drug and weapons trafficking. A national gang report released in 2013 found that the Bandidos were one of five motorcycle gangs seen by law enforcement officials as the most significant threats to public safety.

“These guys are organized crime, but they are also domestic terrorists,” said Cook, who also runs a group called the Midwest Outlaw Motorcycle Gang Investigators Association, which is devoted to combating biker gangs “from the inside.” “These guys are heavily involved in methamphetamine, cocaine, marijuana, motorcycle theft.”

Waco police were well aware of the potential for violence at Sunday’s meeting and had stationed 18 officers nearby — plus four from the Texas Department of Public Safety. That enabled police to respond within 30 to 45 seconds of the first shots being fired, said Swanton, the Waco police spokesman.

“There were multiple people on the scene firing weapons at each other. They then turned on our officers,” Swanton said at a news conference near the restaurant. “Those officers’ reactions . . . to a very hostile, deadly situation saved our citizens’ lives yesterday afternoon.”

Some people fled the restaurant as the chaos unfolded and took shelter behind an empty building. “We sat there gathering our wits,” said J.R., the Cabela’s Outpost employee. “At first you think it’s like a carjacking or something. But then, with all the shots and people running, you realize it’s something more serious.”

Bravo, the waiter at the Mexican restaurant, said he saw emergency vehicles flooding the parking lot seconds after the shooting began. He saw one man wearing a biker’s vest who appeared to have been shot in the abdomen.

Paramedics tried to perform CPR for several minutes, Bravo said, and “then they just covered him up.”

An arrest affidavit filed Monday confirmed the involvement of the Bandidos and the Cossacks. The affidavit states that all 170 people arrested at the scene were “wearing common identifying distinctive signs or symbols” of their respective gangs. In addition, numerous motorcycles with signs or symbols of those two gangs were found at the scene.

So many people were arrested that they were initially taken to the city’s convention center for processing before being taken to the McLennan County Jail, which was still working to process the arrested on Monday.

Swanton was critical of Twin Peaks management, saying the restaurant did not cooperate with police warnings about the potential for violence. The Twin Peaks corporate office in Dallas seemed to agree: The company announced Monday that it was revoking the Waco location’s franchising agreement.

“Unfortunately the management team of the franchised restaurant in Waco chose to ignore the warnings and advice from both the police and our company, and did not uphold the high security standards we have in place to ensure everyone is safe at our restaurants,” the company said in a statement.

Meanwhile, police and residents in Waco were bracing for a potential outbreak of trouble. Police received information about possible “payback” against officers, as well as reports of bikers heading to the area after the fight, Swanton said.

“There was a green light put out on law enforcement, is our understanding from last night,” Swanton said Monday. “We’re aware of that threat, and we have the appropriate response if we have to face that.”

Richard, a Waco engineer and motorcycle enthusiast who declined to give his last name for fear of becoming a target, said regular people with motorcycles are worried, too.

“Ninety-nine percent of the people who ride bikes are good people — doctors, lawyers, engineers,” and the shootout “was a rude awakening for the rest of us,” he said.

“Is this going to land on our doorsteps? Is this what we have to look forward to? What happens if we’re wearing the wrong shirt in the wrong neighborhood? That’s what has a lot of us worried.”

Madigan, a freelance writer, reported from Waco. Berman and Holley reported from Washington. Michael E. Miller and Alice Crites in Washington contributed to this report.