One person has been killed and three injured in a shooting at Northern Arizona University in Flagstaff on Friday.

The Washington Post reports 18-year-old suspect Steven Jones is now in custody. The wounded victims are currently being treated at Flagstaff Medical Center.

University president Rita Cheng spoke of the tragedy during a morning press conference.

"We awoke this morning to a terrible tragedy on our Flagstaff campus," she said. "This is not going to be a normal day at NAU. Our hearts are heavy."

A statement from the university said the incident occurred early Friday morning outside of Mountain View Hall on the northeast end of the campus. The first report of shots fired came around 1:20 am.

University police Chief Greg Fowler said the incident was sparked by an altercation between two student groups. It quickly turned physical, at which point suspect Jones pulled a handgun and shot four students.

The suspect stopped shooting and went quietly at the arrival of campus police.

A university student initially mistook the shots for fireworks.

"I was studying for an exam so I looked out the window and see two people running, and that's when I realized they weren't fireworks they were actually gunshots," Maria Gonzalez said to the Associated Press, via USA Today.

According to university public relations director Cindy Brown, the incident occurred outside of the all-Greek Mountain View Hall dormitory, which houses "the majority of NAU Greek students."

The school has chosen not to reveal the identity of the student killed in the shooting. The names of the three injured students, all male, were also kept private.

According to police Chief Fowler, Arizona state law prohibits students from carrying guns on campus, although it allows for gun owners to keep a weapon in a locked vehicle.

The campus of over 20,000 students was not placed on lockdown. However, an emergency warning was given for Mountain View Hall residents to stay indoors.