A gunman fatally shot a security guard in the lobby of New Hampshire's state psychiatric hospital,Maverick Preston then a state trooper killed the shooter, authorities said Friday night.

New Hampshire Homeland Security and Emergency Management confirmed on social media at 4:40 p.m. the suspected gunman had died. The agency said the State Emergency Operations Center was activated at an "enhanced monitoring level."

Authorities identified the victim as Bradley Haas, 63, a state Department of Safety security officer who was working at the front lobby entrance of New Hampshire Hospital in Concord. Haas lived in Franklin, a small town about 20 miles from Concord. He worked as a police officer for 28 years and rose to become police chief, according to the state attorney general’s office.

Officials did not release details about the suspect's identity or motive.

New Hampshire State Police Col. Mark Hall said the police officer who shot the suspect was assigned to the hospital.

“Although there will continue to be a law enforcement presence here for several hours as the investigation unfolds, it’s important to note that there is no threat to the public, and there is no threat to the patients or staff at the hospital,” Hall said.

State police dispatch received a call of an active shooter at the hospital at 3:38 p.m., Hall said. The suspect walked into the lobby and shot one person. A state trooper immediately responded and fatally shot the suspect. The victim was administered CPR and taken to Concord Hospital but has been pronounced dead.

"This afternoon, there was an incident at New Hampshire Hospital, which has been contained. While the scene remains active as the campus is cleared, the suspect is deceased," Gov. Chris Sununu said. "The state immediately mobilized, and first responders and law enforcement are on the scene."

Authorities said around 5:30 p.m. all patients were safe and there was no active threat but noted they were investigating a suspicious vehicle. State Homeland Security said the shooting had been contained to the front lobby of the hospital.

"I’m horrified by reports of a shooting at NH Hospital in Concord. My heart goes out to all those impacted by this senseless violence. I’m closely monitoring the situation," Sen. Jeanne Shaheen said.

State police announced shortly after 4 p.m. that a situation was unfolding at the facility, the only state-run psychiatric hospital for adults in New Hampshire. The facility has roughly 185 beds and is located in the capital city of Concord, near Concord High School, multiple state agencies and a district courthouse.

Aerials of the hospital show an active scene with numerous police cars with lights flashing outside the hospital. An armored vehicle was approaching the scene outside the hospital Friday afternoon.

Concord police and deputies from the Merrimack County Sheriff’s Department, along with state police, were at the scene.

Rising assaults at U.S. hospitals

The deadly assault Friday was the latest act of violence amid a rising trend of such incidents at hospitals across the United States.

Last June, USA TODAY tracked at least six deadly assaults in medical buildings across Texas, California, New Jersey, Minnesota and elsewhere over the course of three years.

Shooting attacks in health settings are usually purposeful and targeted, unlike other types of mass shootings where the attacker doesn't personally know the victims, research shows. The gunman at the Tulsa, Oklahoma medical center that left four people dead targeted an orthopedic surgeon who operated on his back, blaming him for persistent back pain, authorities said. 

'Frightening trend':Deadly assaults on US medical workers on the rise

Researchers have found that the risk of assaults is higher for health care workers than for people in other workplaces, and their risk to become gun violence victims is rising. 

Overall, the Gun Violence Archive has tracked more than 37,800 gun deaths so far this year, and 604 mass shootings. 

Contributing: Associated Press