Two men were shot in the parking lot of San Francisco's Candlestick Park and a third was brutally assaulted inside the stadium after a preseason National Football League game between the San Francisco 49ers and the Oakland Raiders, police said Sunday.

A 24-year-old man was taken to the hospital with life-threatening injuries after he was shot up to four times in the stomach in the parking lot for wearing a T-shirt with a derogatory comment about the 49ers. Another man in his 20s sustained lesser injuries after he too was shot at a different location in the parking lot outside the game.

In another incident, a 26-year-old man was beaten unconscious with life threatening injuries after a fight broke out in a washroom at the stadium.

Police said that there are no suspects in custody. The suspect in the bathroom beatings was described as a Samoan or Pacific Islander between 25 and 30 years old, weighing 225 to 260 pounds and 6-foot-3 to 6-foot-5 inches tall, reports the Los Angeles Times.

Police are investigating the shootings but are still unsure if the two attacks outside the stadium are related. It was not immediately clear if any of the men who were shot were fans of any particular team.

The 24-year-old man, who was shot, managed to drive himself to a stadium security official for help, police said.

The violence occurred during and after the Bay Area preseason showdown between the 49ers and Raiders Saturday night. The 49ers won 17-3.

Sgt. Michael Andraychak of the San Francisco Police Department told the Los Angeles Times stadium security tends to be extra vigilant during games between teams with a particularly strong rivalry or whose fans have a history of violence.

Fans who attended the game posted videos online depicting the mayhem and belligerent behavior of fans in the stands during the game, added the report.

Watch the video:

The incidents at Candlestick Park last night after the San Francisco 49ers versus Oakland Raiders game are completely unacceptable, and will be prosecuted to the fullest extent of the law, San Francisco Mayor Ed Lee and Oakland Mayor Jean Quan said in a joint statement about the violence.

The NFL also condemned the violence and said: We deplore the activities of a handful of fans at last night's game and pledge our full support to Mayors Lee and Quan and to state and local law enforcement agencies.

We are carefully reviewing the events to make sure we have a full understanding of the facts.

In March, San Francisco Giants fan Bryan Stow was severely beaten by two men in Los Angeles Dodgers gear outside Dodger Stadium after the teams' season opener. He remains in San Francisco hospital with in serious condition with brain injuries. Two suspects have been charged in the case.