Editor's Note: (Latest coverage of the Tulsa hospital shooting can be found here.)
(CNN) At least four people were killed Wednesday in a shooting on a hospital campus in Tulsa, Oklahoma, police said in a news conference Wednesday evening.
The gunman is also dead, police said. Authorities believe the shooter's gunshot wound was self-inflicted, Tulsa Police Department Deputy Chief Eric Dalgleish said in the news conference.
Several people were also wounded, though no one has life-threatening injuries, police Capt. Richard Meulenberg told CNN on Wednesday night.
Dispatchers received a call about an active shooter at the Natalie Medical Building, a physicians' office building on the St. Francis Hospital campus, shortly after 4:50 p.m. local time, Dalgleish said.
Officers responded to the scene within minutes and made contact with victims and the suspect roughly five minutes later, Dalgleish said. The officers who arrived could hear shots inside the building, which directed them to the second floor, according to the deputy chief.
"The scene is fairly limited to one section of that floor, on the second floor," Dalgleish said. At least part of the scene was in an orthopedic office on that floor, according to Dalgleish.
No officers were injured, he added.
Investigators are interviewing witnesses that were in the building, Dalgleish said. One witness was found locked in a closet, he said.
Police said they are "getting close" to identifying the suspect, who Dalgleish said had one rifle and one handgun with him. "It appears both weapons, at one point or another, were fired," the deputy chief said.
Authorities were notifying the victims' families Wednesday night, Meulenberg told CNN.
"It's a horribly tragic event," Meulenberg said. "I'm very, very proud of the officers for getting there as quickly as they did, very well potentially stopping more people from losing their life today."
Tulsa Mayor G.T. Bynum expressed "profound gratitude" for the first responders who "did not hesitate today to respond to this act of violence."
"The men and women of the Tulsa Police Department did not hesitate," the mayor said.
Earlier Wednesday, Meulenberg said authorities had to evacuate "multiple floors" of the building.
"It was just madness inside, with hundreds of rooms and hundreds of people trying to get out of the building," Meulenberg told CNN Wednesday night.
There has been a reunification site set up for family members and friends at Memorial High School west of LaFortune Park, police added.
"There is nothing more this community could do for us than to pray for the families and the loved ones and the victims of this senseless act," Cliff Robertson, the Saint Francis Health System CEO, said in the news conference.
President Joe Biden has been briefed on the shooting, a White House official said. The White House is closely monitoring the situation and has reached out to state and local officials to offer support.
The Bureau of Alcohol, Tobacco, Firearms and Explosives is also assisting on scene, the ATF Dallas Field Division said on Twitter.
"What happened today in Tulsa is a senseless act of violence and hatred," Oklahoma Gov. Kevin Stitt wrote on Twitter. "I am grateful for the quick and brave actions of the Tulsa Police Department and other first responders who did their best to contain a terrible situation."
In a statement posted on Facebook the Saint Francis Health System wrote all appointments in certain locations scheduled before noon Thursday have been canceled "to allow our staff and caregivers the opportunity to process today's tragic incidents."
"Additionally, the Warren Clinic Orthopedic offices in the Natalie Building will be closed for the balance of the week," the system wrote.
Debra Proctor was in another building on the hospital campus for a doctor's appointment when she heard police sirens ringing out.
When she stepped outside, first responders were lined up everywhere, she told CNN. Proctor, who has been a registered nurse for more than four decades, said it was a "shocking" scene.
"Police were everywhere in the parking lot, up and down the surrounding blocks," Proctor said. "They were still arriving when I was leaving."
Kalen Davis, a lifelong Tulsa resident, was waiting in traffic around 5 p.m. local time when she saw multiple police cars responding to the scene.
In a video she shared with CNN, authorities can be seen running toward a building with their guns drawn. Two officers are seen taking long guns out of their trunks as more emergency vehicles race to the scene.
"I just knew that it was a shooting situation because I saw police running with rifles," Davis, 45, told CNN. "That's when I got emotional."