In response to the rambunctious and at times destructive mayhem that erupted in Dinkytown after the Minnesota Gophers' NCAA semifinal hockey victory over archrival North Dakota, university President Eric Kaler told students Friday that a substantial law enforcement presence will be in place to stymie a repeat when the team plays Saturday night for the national championship.

Thursday night's unrest, a milder reprise of the Frozen Four mayhem in 2002 and 2003, drew police in riot gear as Gophers fans converged, with some climbing on light poles and cars and taking selfies as the crowd grew. According to social media reports, some were belligerent toward police officers as they arrived to disperse the crowd.

Minneapolis police said two of its officers were slightly hurt and required medical attention after helping quell the two hours of unrest that also left "an undetermined amount of public and police property" damaged. Nine students were arrested on misdemeanor charges.

"The actions of a few people in Dinkytown last night unfortunately marred the victory of our Gophers men's hockey team," Kaler wrote in an e-mail to students. "These actions are unacceptable and must not be repeated."

Kaler said that any similar outbreak of misbehavior Saturday after Minnesota's game against Union "will be met with zero tolerance."

The president said that campus and city police and "other law enforcement from across the metro area" will be on duty "to keep the peace and arrest suspects."

University Police Chief Greg Hestness said Friday afternoon that "planning for Saturday has been underway for two months."

In a statement, Minneapolis police said it hopes people "celebrate responsibly and lawfully" after the championship game.

"If celebrations escalate into criminal behavior, the MPD will act to ensure public safety and protect property," the statement continued. "Anyone told to disperse from an assembly that has been declared unlawful must immediately leave the area. Failure to do so may result in an arrest."

Hours before Kaler's e-mail, student Nathan Lyons, who watched dozens clamber on top of a squad car Thursday night, said, "Whether the Gophers win or lose, it's going to be out of hand."

Looking ahead to Saturday night, university leaders said Friday that students face the possibility of arrest even if they are doing no more than standing by and watching any unruliness.

"If you are here, you are part of the incident and you are subject to arrest," Pam Wheelock, vice president for university services, said during a Dinkytown street corner news conference.

Kaler said in his e-mail that if the situation is getting out of hand, "it's best for you and your friends to leave. In this era of social media, no one is anonymous."

Nine students were among those arrested, Wheelock said, and they face disciplinary hearings that could result in a range of punishment, from a warning to community service to suspension to expulsion.

At least five of the code's 21 defined disciplinary offenses could apply: disorderly conduct, stealing or damaging property, disruptive behavior, rioting and committing crimes. The code also cautions that violations, even they occur off campus, can draw university punishment.

Joining Wheelock and others Friday was student body President Mike Schmit, who said he was embarrassed by how his fellow students behaved and pleaded for calm Saturday.

"When the Gophers win the national championship tomorrow night, I encourage you to find a way to celebrate that doesn't include trashing Dinkytown."

An amendment to the code in 2003 added rioting specifically in response to the Dinkytown unrest in April, university spokesman Steven Henneberry said. The code was amended again in 2006 to ensure that misbehavior off campus and in connection with university events could also draw punishment, he said.

Minneapolis police spokesman John Elder said some students threw beer bottles and cans at officers and a couple of squad cars were damaged. One video showed several young men climbing on a squad car and jumping on its trunk, roof and hood.

A State Patrol helicopter was called to illuminate the area.

Court and jail records Friday show up to 10 arrests in connection with the overzealous celebrating, with most or all being U students. Charges of disorderly conduct and unlawful assembly the most common of the misdemeanor violations. But the number arrested could rise, if police succeed in getting citizens to turn in incriminating evidence.

The department "is currently reviewing video footage and actively investigating last night's criminal behavior," a police statement issued Friday afternoon read. "We encourage witnesses who have video or other evidence that might be helpful to investigators to contact the Minneapolis police tip line at 612-692-TIPS (8477)."

In 2002 and 2003, when the Gophers won national hockey titles, police and emergency personnel dealt with unruly fans, arresting several people. They also dealt with vandals and many small fires in Dinkytown.

One of those busted in 2002 was then-student Tony Smith, now living in the Los Angeles area. Smith said Friday he wants to warn current students not to get carried away Saturday, win or lose.

"Party inside," said Smith, who had to pay $5,500 for bringing down a light pole and perform many hours of community service picking up trash and working t a recycling center. "One thing leads to another, and you get caught up in the moment. … It can embarrass yourself and your family."

Leading up to Thursday night's NCAA semifinal game in Philadelphia over a spirited rival in North Dakota, police initiated a door-knocking effort to alert residents to the potential for hockey-related misbehavior. Also, a universitywide e-mail was sent before the weekend addressing how students should comport themselves.

A 21-year-old Minnesota student was among those arrested, but she contends that she did nothing wrong. "I happened to be standing there," she said. "I was telling my peers that it was ridiculous that we were rioting over a hockey game."

Her most immediate concern, now that she posted $78 bail early Friday and is out of jail, is to "make sure this doesn't affect my graduation in the spring," she said. "I just want to get as far away from Dinkytown as possible."

Things could have spiraled out of control if police hadn't shown up in large numbers, said Lyons. "It would have gotten out of hand," the student said. "The cop car would have been destroyed."

An hour after the action died down, U student Haley Larson said, she and others sat on the front steps of a Dinkytown house sharing videos from the night.

Student Kallie McBride said she saw police officers shoot paint pellets or tear gas at students. "People near me were hit," she said.

One group of students saw a trash can set on fire, posed for pictures next to it, and moments later ran as Minneapolis police fired a paint pellet at them.

"Did you see the little arsonist back there?" asked one of the officers. "He'll have green paint on him."

Streets were mostly calm by 1 a.m. Friday, though sporadic confrontations continued in the neighborhood around Dinkytown's business district.