Two people died and at least four were injured in a shooting incident at the University of North Carolina’s Charlotte campus in the United States on Tuesday, AP reported. Three of the injured are in a critical condition.

The police said they have charged 22-year-old Trystan Andrew Terrell, who is in custody, with two counts of murder and four counts of attempted murder, Reuters reported. Sandy D’Elousa, a spokeswoman for the Charlotte-Mecklenburg Police Department, said Terrell was acting alone.

The campus initiated a lockdown soon after the shooting, which also led to widespread panic. Campus police chief Jeff Baker said the authorities received a call late in the afternoon that a person was armed with a gun and had shot several students. Officers who had gathered for a concert nearby went to the building, he said, adding: “Our officers’ actions definitely saved lives.”

The University of North Carolina’s Office of Emergency Management had issued an alert around 6 pm that shots had been fired. “Run, Hide, Fight. Secure yourself immediately,” it said. Tuesday was the last day of classes for the academic year, according to AFP.

Scheduled activities such as examinations, will be cancelled till Sunday, university chancellor Philip Dubois announced, according to NPR.

“We are in shock to learn of an active shooter situation on the campus of UNC Charlotte,” Charlotte’s mayor Vi Lyles said on Twitter. “My thoughts are with the families of those who lost their lives, those injured, the entire UNCC community and the courageous first responders who sprang into action to help others.”