A screen capture of a filmed brawl at a pre-season game between the Raiders and 49ers

The 49ers and San Francisco Mayor Ed Lee announced a crackdown on violence and drunkenness during football games at Candlestick Park, as new details emerged about a night of bloody mayhem unmatched by any previous Bay Area sporting event.

During and after Saturday night’s preseason game against the Raiders, more than 50 people required medical attention – five times more than during an average regular-season game – and 10 people were taken away by ambulance. More than 70 fans were ejected, San Francisco police reported.

Despite a police presence that was 40 percent larger than normal, two men were shot in the parking lot, another was savagely beaten in an upper-deck bathroom and dozens of brawls broke out in an atmosphere fans described as out of control even as authorities called in for backup starting in the second quarter.

The father of one of the victims, a 24-year-old 49ers fan who was shot four times in the stomach, said in an interview that his son's condition was improving after doctors at San Francisco General Hospital repaired his colon and replaced a large part of his intestines. The other shooting victim, who was shot in the face, was also in fair condition, according to authorities.

Lee, flanked by Niners owner Jed York, San Francisco Police Chief Greg Suhr and other officials, announced several security changes Monday, including a ban on tailgating during and after games and DUI checkpoints after games. In a letter to fans, York said he is recommending to the NFL that it "suspend the preseason series between the 49ers and Oakland Raiders."

"The degenerate behavior that happened on Saturday is not going to be tolerated," York said.

San Francisco police said officers will patrol the access roads around Candlestick before parking lot entry gates are opened before games. Officers will enforce state and local laws barring open containers and consuming alcohol, police said.

As more witness accounts continue to surface, it has become clear that violence marred much of the fan experience during the game. Jim Mercurio, the 49ers’ vice president for stadium operations & security, said: "In my 19 years of doing this, never have I had to deal with the amount of calls for service, the amount of fights, the amount of behavior that is absolutely not accepted."

The father of one of the victims, identifying himself only as Jack to protect his son's identity, denied the shooting was gang-related, as some reports have suggested.

“My son is not involved in a gang," he said. "The only gang he's involved with is the gang called the Niners. He goes to the 49er games because he likes football. He didn't go to the game to get shot or fight.”

Jack said Monday that his son has a job and is the father of a 10-month-old baby boy who took his first steps just before Saturday's game.

He said his son was wearing a 49ers jersey and a white leather 49ers jacket and attended the game with three friends, all dressed in 49ers gear. They were walking to their cars after the game when the group of friends noticed the crowd growing rowdier. They split up and sped up to walk to their cars, when one of the friends was attacked by a group of men in Raiders shirts.

The friend was pummeled and kicked on the ground, according to Jack's account. As the others tried to pull the men off, Jack's son sped over in his truck and got out to help.

“He didn't even get two steps from the car,” the father said. “All of a sudden they heard, 'bang, bang, bang.'”

Witnesses told Jack his son moaned and collapsed, and then stumbled back into his truck.

“Out of panic, he thinks he's going to take himself to the hospital," he said. "He only got so far as the gate, opened his door and collapsed.”

Another man at the security gate called 911. Jack's son is in stable condition and is expected to recover, his father said.

While some fans Monday remained shocked, others said the violence has become a norm, particularly at Raiders and Niners games. Videos and fan testimony revealed brawls inside the stadium that went seemingly unchecked by security and police. Police released a timeline Monday outlining their response to the fighting.

“Is anyone really surprised?” said Dom Arotzarena, president of the Oakland Police Officers Association. Oakland police officers, Alameda County Sheriff's personnel and private security provide security at Raiders games. “I'm not. This is nothing new.”

League officials, on the other hand, characterized the violence as out of the ordinary.

“We deplore the activities of a handful of fans at [Saturday] night's game between the 49ers and the Raiders,” the NFL said in a statement.

Authorities say they take into account the bitter rivalry when assigning officers to stadium details. In Oakland, police said about 200 officers are on hand for the games, in addition to stadium security.

San Francisco police spokesman Sgt. Mike Andraychak said the department also had additional officers at Saturday's game. The team checks bags and provides fans with rules for tailgating and attending the game upon entering the parking lot and the stadium. Officers patrol the perimeter and inside Candlestick.

“You can have as much security as you want, if something's gonna happen it's gonna happen,” said Lt. Bill Roaldes, who oversaw last season's stadium security.

Still, some stadiums that previously defended their security have made changes after violent attacks. After San Francisco Giants fan Bryan Stow was seriously beaten earlier this year at the Los Angeles Dodgers' home opener, the team hired Kroll, a consulting company, to develop a new security plan.

Bill Bratton, chairman of Kroll and the former chief of the LAPD, said the Dodgers have since increased the lighting in their parking lots and increased the number of uniformed officers at games, among other adjustments.

Bratton said newer stadiums are now built with design elements that are not present in some older venues, such as Candlestick. Ideally, he said security should have platforms that allow officers to view everything going on in the parking lots. Many stadiums are now also built with more entrances and exits, to allow crowds to disperse quickly and easily, rather than gather in a mob. Some other best practices include barring problem fans from entering the ballpark, and having fans pass through metal detectors, which neither the Niners nor the Raiders use, although both teams inspect fans' bags and backpacks.

“It's of greatest importance to keep weapons from coming into the venue, so you don't have an incident in the venue. That's why often times things are happening in the parking lots, because they can keep weapons in their cars.” Bratton said. “There will always be incidents, but the idea is to try to prevent them to the best of your ability.”

Bay Citizen reporter Gerry Shih contributed to this report.