UPDATE:
Tulsa Police Captain Richard Meulenberg said the shooter was reported "down" around 5.30 p.m. on Wednesday and the situation at the St. Francis Hospital campus, which was active about four to five minutes, was being treated as "a catastrophic scene", reports Xinhua news agency.
"We know there are multiple injuries, and potentially multiple casualties," the Police Department said in a Facebook post.
The shooter was armed with a rifle and a handgun and fired both weapons at the Natalie Medical Building, a physicians' office on the premises, according to Tulsa Police Deputy Chief Eric Dalgleish.
Dalgleish said the shooter's fatal wound was self-inflicted.
Police have not identified victims or anyone specifically targeted by the gunman.
Wednesday's incident comes after 19 children and two teachers were killed on May 24 in a mass shooting at the Robb Elementary School in Uvalde, Texas.
There have been 213 mass shootings in the first 21 weeks of 2022 in the US, including 27 school shootings and up to approximately 10 mass shootings every week, according to the Gun Violence Archive.
President Joe Biden has been briefed on the Tulsa shooting, White House officials said in a statement.
On May 28, President Biden urged Americans to make their voices heard to prevent further gun violence, following the Uvalde massacre.
EARLIER STORY:
TULSA, Oklahoma (AP) — Three people were killed Wednesday in a shooting at a Tulsa medical building on a hospital campus, a police captain said.
Capt. Richard Meulenberg confirmed the number of dead. Meulenberg said the shooter also was dead.
It was unclear how the shooter died.
“Officers are currently going through every room in the building checking for additional threats,” police said in a Facebook post just before 6 p.m. “We know there are multiple injuries, and potentially multiple casualties.”
Meulenberg also said multiple people were wounded and that the medical complex was a “catastrophic scene.”
St. Francis Health System locked down its campus Wednesday afternoon because of the situation at the Natalie Medical Building. The Natalie building houses an outpatient surgery center and a breast health center.
Aerial footage from a TV helicopter appeared to show first responders wheeling someone on a stretcher away from the hospital building.
Dozens of of police cars could be seen outside the hospital complex, and authorities shut down traffic as the investigation went on.
A reunification center for families to find their loved ones was set up at a nearby high school.
Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were also at the scene, a spokesperson said.