A gunman shot dead four persons on a hospital campus in Tulsa city of Oklahoma in the United States on Wednesday, the police told the Associated Press.

The shooter, who was carrying a rifle and a handgun, also died, apparently from a self-inflicted gunshot wound, Tulsa Police Department Deputy Chief Eric Dalgleish told AP.

“It appears both weapons at one point or another were fired on the scene,” Dalgleish told AP. “The officers who arrived were hearing shots in the building, and that’s what led them to the second floor.”

The shooting took place at a section of the second floor of the Natalie Medical Building on the campus of Saint Francis Hospital, he told The New York Times. The gunman’s identity has not been revealed, but police estimate he was aged between 35 and 40.

The police were notified about the shooting at 4.52 pm local time, and arrived at the scene within four minutes, he added. It was not clear how many others were injured in the attack but they do not have any life-threatening wounds.

Saint Francis Hospital shut down its campus on Wednesday after the shooting, AP reported. The Natalie Medical Building houses an orthopaedic clinic, outpatient surgery centre and a breast health centre.

Tulsa Mayor GT Bynum said his thoughts are with the victims. “For decades, this campus has been a place where heroes come to work every day to save the lives of people in our community,” he said, according to AP.

The White House said that United States President Joe Biden has been briefed about the shooting. “The White House is closely monitoring the situation and has reached out to state and local officials to offer support,” it said.

The Oklahoma shooting comes amid a spate of mass shootings in the United States. On May 24, a gunman shot dead 19 children and two adults at the Robb Elementary School in Texas.

The attack was carried out by 18-year-old Salvador Ramos, who was eventually killed by responding officers. Ramos had shot his grandmother before attacking the school. Ramos had also posted about his plans on Facebook.

The officers came under fire for waiting for nearly an hour outside the school. The incident sparked nationwide debate with the ruling Democrats calling on gun control, and the Republicans demanding better security at schools, AP reported.