Two other people are being treated for life-threatening injuries, and two more people have non-life threatening injuries, the agency said.
One person is in custody, Charlotte-Mecklenburg police tweeted
. "No reason to believe anyone else involved," they wrote.
Law enforcement officers were sweeping several buildings, the university and police tweeted.
"Follow officer commands," the school said.
Video posted to twitter by Jordan Pearce, a student, showed people fleeing a campus library as police sprinted toward the building.
An image posted by Pearce shows a door where the glass is all over the floor inside a building.
The university, which has 30,000 students, tweeted: "Campus lockdown continues. Remain in a safe location. Monitor email and UNCC homepage.
Tuesday was the last day of classes, with exams to begin on Thursday.
Charlotte-Mecklenburg police are assisting university police in the case.
Developing story -- More to come