STORY: "Right now we have four civilians that are dead," Tulsa deputy police chief Eric Dalgleish said. "We have one shooter that is dead and right now we believe that is self-inflicted," he said.
Officers were still working to clear the St. Francis Hospital campus, and a press briefing was scheduled for 1915 (0015 GMT).
The White House said President Joe Biden had been briefed on the shooting and that it is "closely monitoring the situation and has reached out to state and local officials to offer support."
The Tulsa shooting follows two mass shootings in May that shocked Americans and reignited debates about gun control. Last week, a gunman killed 19 children and two teachers at an elementary school in Uvalde, Texas. Earlier in May, a shooter killed 10 people at a supermarket in Buffalo, New York.