The gunman, identified by authorities as Diogenes Archangel Ortiz, 49, was also killed, authorities said.

Two other law enforcement officers were shot by the gunman and are in stable condition, York County District Attorney Tim Barker said at an afternoon news conference.

An intensive care unit doctor, nurse and a custodian suffered gunshot wounds and a fourth employee was injured in a fall, according to Barker.

The gunman had arrived at the hospital carrying a bag with a handgun and zip ties and went straight to the ICU, where he held staff members hostage, Barker said.

Officers were preparing to confront the gunman and breach the ICU when Ortiz held an ICU employee hostage at gunpoint and ordered police to get back, according to Barker.

“They did, so the person being held hostage would not be harmed, and were attempting to try to engage in discussion with Mr. Archangel Ortiz,” Barker said.

The woman being held hostage also had her hands tied with zip ties, according to Barker.

When Ortiz came out into the hallway still holding the ICU employee at gunpoint, the officers opened fire and fatally shot Ortiz, Barker confirmed.

The incident appears to have been specifically targeted at the ICU, Barker said. In the previous week, the gunman was in contact with the ICU for a medical purpose involving another individual, according to Barker.

“No patients have been injured. The hospital is now secure,” Susan Manko, spokesperson for UPMC Memorial in York, told CNN.

“He was someone who put on the uniform of service and went out to try and keep his neighbors safe,” Pennsylvania Gov. Josh Shapiro said at the news conference. “He is to be commended for a life of service, albeit cut way too short from a life of service to others. We’re deeply grateful to him.”

“Officer Duarte’s bravery and commitment to upholding the law are a testament to the selflessness shown daily by those who have dedicated themselves to protecting and serving,” the statement read.

Witnesses describe scene of shooting

Jayden Robertson and his grandmother were visiting his aunt’s hospital room on the fourth floor at UPMC Memorial on Saturday morning when an announcement was made about an intruder with a weapon.

At first, they didn’t think much of it, assuming it might just be “a little kid who forgot he had a pocket knife in his pocket or something like that,” Robertson told CNN.

It wasn’t until a friend texted him a news report stating there had been a shooting at the hospital he and his family fully understood the gravity of the situation.

When Robertson looked out the window, he saw many police cars and officers running to their vehicles to grab guns and shields.

In the same building, Betsy Small was visiting her mother at the hospital around 10:30 a.m. when she started to hear “strange noises, a lot of activity, and then alarms going off.”

When she looked out the window, people were running, she said, and a woman announced something about a “lockdown” over the intercom system.

“I thought, oh something’s going on in here, but you never think it’s going to be a shooting, not in a hospital,” Small, 58, told CNN.

When the alarms went off, Small said she believes her hospital room door locked. She crouched down on the floor near the window for safety, her mother fast asleep in her hospital bed throughout all the commotion.

Within minutes, three or four police cars had arrived and officers were running into the building with shields and guns, she said she saw through the hospital room window.

For the next hour or so, Small watched through the hospital door window as nurses ran back and forth on her floor while yelling at one another.

At 11.41am, her daughter texted her that a shooter “had been taken out”.

As of 3pm, Small was not yet allowed to leave the building and said she has seen some of the nurses crying with one another in the hallway.

“I feel sad for everybody, honestly I do. It’s a sad situation,” Small said.

Shapiro said during the news conference state and local leaders will work with affected health care workers to ensure they have the resources to heal.

“I know that the trauma that the health care workers here today had to deal with is not something that goes away overnight,” Shapiro said.

“Every day when you put on your white coat or your uniform of service to others here in this wonderful hospital, or any hospital across Pennsylvania, you are performing that function because you care about your neighbors and you want to make sure that they are healthy and safe. Something like this should never, ever happen in your place of work.”

“Our hearts go out to the victims, their families and all those affected by this senseless act of violence,” Keefer and Grove said, thanking first responders “for their swift actions in securing the scene, treating the wounded and ensuring the safety of our community.”