MINNEAPOLIS (AP) — University of Minnesota students were warned Friday that a heavy police presence will be in place during the national hockey championships to prevent a repeat of the riotous behavior that erupted after Minnesota edged North Dakota in the Frozen Four semifinals.

Thursday night’s unrest drew police in riot gear as hundreds of students and other hockey fans took to the streets in Dinkytown near campus to celebrate the Gophers’ last-second win. Some fans threw beer bottles and cans at officers, others climbed light poles, and one video showed several young men jumping on top of a squad car. A State Patrol helicopter was called to illuminate the area.

Police arrested several people, and two officers were taken to Hennepin County Medical Center for, Minneapolis police said Friday. An undetermined amount of public and police property was damaged during the two-hour disturbance, police said.

“The actions of a few people in Dinkytown last night unfortunately marred the victory of our Gophers men’s hockey team,” University of Minnesota President Eric Kaler wrote in an email being sent to students Friday. “These actions are unacceptable and must not be repeated.”

Kaler said that any similar outbreak of misbehavior Saturday after Minnesota’s game against underdog Union in Philadelphia, “will be met with zero tolerance.”

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

Campus Police Chief Greg Hestness said Friday that “planning for Saturday has been underway for two months.”

In a statement, the Minneapolis Police Department said it hopes people “celebrate responsibly and lawfully” after the championship game.

Kaler said that troublemakers not only risk prosecution but discipline under the school’s Student Conduct Code.

Minneapolis police are reviewing video footage of the raucous celebration and are asking the public for any video that might help investigators.

In 2002 and 2003, police and other emergency personnel dealt with unruly, vandalizing fans when the Gophers won national hockey titles.