Lee attended Saturday’s game at Candlestick Park in San Francisco with Oakland Mayor Jean Quan, and both witnessed the brawling firsthand as spectators.

"They were just constantly wailing at each other without regard to who was there," Lee said of the fans. "This is a family outing, for residents and visitors and people who want to see the game, not for people to look for people they don’t like, then saying bad words, then getting into it."

Lee said he is working with police and the 49ers on security issues and to review footage of the fights and help identify people involved. A meeting was planned later Monday.

Meanwhile, two men who were initially listed as seriously injured in the violence have been upgraded to fair condition by a hospital.

One of the victims, a 24-year-old man who reportedly was wearing a T-shirt reading "F— the Niners," was shot several times in the stomach. Police said he managed to make it to stadium security for help despite the injuries.

The other victim whose condition was upgraded is a 26-year-old man who was beaten unconscious in an upper level stadium restroom during the fourth quarter.

Another shooting victim was treated after receiving superficial facial wounds after the game.

Police did not release the name of any victims. No arrests have been made.

Investigators were searching for suspects and interviewing witnesses, said Officer Albie Esparza, a San Francisco police spokesman.

Police also were seeking motives in the shootings, including whether the attacks were influenced by emotions involving the annual Battle of the Bay exhibition game or possibly gang connections.

The shootings evoked memories of the near-fatal beating in March of a San Francisco Giants fan outside Dodger Stadium. The Giants and Dodgers baseball teams also are fierce rivals.

Esparza said police are still looking for a person of interest connected to at least one of the shootings at the football game. He would not specify which shooting.

The crimes previously prompted Lee and Quan to issue a joint statement condemning the violence and saying it will not be tolerated at stadiums in either city.

NFL spokesman Greg Aiello echoed similar concerns, saying the league deplored the activities and pledged to support the mayors and law enforcement.

Raiders CEO Amy Trask also said the incidents were not acceptable to the Raiders or to any National Football League team and "our thoughts are with all affected."

Police Sgt. Frank Harrell said the man who was wearing the T-shirt drove his truck to a gate and stumbled to stadium security.

He said the two shootings were being treated a separate incidents but were likely related.

The attacks come nearly five months after San Francisco Giants fan Bryan Stow was severely beaten by two men in Los Angeles Dodgers gear outside Dodger Stadium after the archrivals’ season opener.

Two men charged in the beating, Louie Sanchez, 28, and Marvin Norwood, 30, have pleaded not guilty.

Stow, 42, a Santa Cruz paramedic, suffered severe brain injuries and remains hospitalized in serious condition.

Christian End, an assistant professor at Xavier University in Cincinnati, who specializes in sports fan behavior, said there are several factors for unruliness at sporting events — including the magnitude of the game, if it is between arch rivals, adrenaline and alcohol. There’s also "deindividuation," when fans supporting a particular team adopt a group mentality and may become uncivil.

End said he doesn’t believe fan violence has increased in the past 10 years but it may appear that way partially due to new technology that captures such incidents.

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Associated Press Video Journalist Haven Daley and AP sportswriters Janie McCauley in Oakland and Josh Dubow in Alameda contributed to this report.