Police work at the scene of a shooting at New Hampshire Hospital on Friday. Geoff Forester/The Concord Monitor via AP

CONCORD, N.H. — A shooter killed a security guard in the lobby of New Hampshire’s state psychiatric hospital on Friday before being fatally shot by a state trooper, officials said.

The shooting happened around 3:30 p.m. at New Hampshire Hospital and was contained to the front lobby of the 185-bed facility, State Police Col. Mark Hall said at a news conference. He said CPR was performed on the victim, who later died at Concord Hospital.

Authorities identified the victim Friday night as Bradley Haas, 63, a state Department of Safety security officer who was working at the front lobby entrance.

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 a statement from the state attorney general’s office.

All patients at the psychiatric hospital were safe, and the state trooper who killed the shooter was not wounded, according to authorities.

“Investigators with the New Hampshire State Police have searched and cleared a suspicious box truck near the scene. They determined the truck poses no safety risk,” the statement from the attorney general’s office said.

No further information was released about the shooter, a possible motive or other details of the attack. But authorities planned to provide an update on the investigation Saturday morning.

Friday’s shooting was the latest act of violence at a U.S. hospital. Medical centers nationwide have struggled to adapt to the growing threats, which have helped make health care one of the nation’s most violent fields.

The shooting happened three weeks after police say Robert Card of Bowdoin entered Just-in-Time Recreation and Schemengees Bar and Grille in Lewiston on October 25, leaving 18 dead and 13 injured. A manhunt ensued looking for Card, who was later found dead.

The hospital remained in operation but was closed to visitors Friday evening, said Lori Weaver, commissioner of the Department of Health and Human Services

“This is a difficult and unimaginable day for our employees and for our community,” she said. “We will continue to make resources available in the coming hours and days.”

“Our dedicated staff will continue to provide skilled, compassionate care as they do every day,” she said.

The facility is the only state-run psychiatric hospital for adults in New Hampshire. Located in the capital city, it is part of a large state office park that includes multiple state agencies and is near the city’s high school and district courthouse. The Department of Safety provides security for the hospital.

Democratic U.S. Rep. Annie Kuster called the shooting “horrifying” in a statement that asked the public to stay away from the hospital while police were still on the scene.

“Thank you to the State Police Officers who responded to the scene so quickly,” Kuster said in a statement. “My thoughts are with the victim, their family, and the Concord community.”

Other members of the state’s congressional delegation also released statements of support.

“The state immediately mobilized, and first responders and law enforcement are on the scene,” Gov. Chris Sununu said in a statement. “We will provide as many details as possible as this situation unfolds.”

AP reporter Holly Ramer contributed from Concord, New Hampshire. Reporters Patrick Whittle and David Sharp contributed from Portland, Maine.