A man armed with a rifle and handgun opened fire on Wednesday inside a medical center in Tulsa, in the US state of Oklahoma, reported DW, quoting news agencies AP and Reuters.
The gunman killed four people, police said.
According to police, the gunman also died. It was not immediately clear how. The motive of the attack isn't clear either.
Tulsa has a population of around 411,000 and is located 160 kilometers (100 miles) northeast of the state capital Oklahoma City.
What do we know about the shooting?
Captain Richard Meulenberg told the ABC broadcaster that local police received a call about a man with a rifle on the second floor of a building on the medical campus.
Meulenberg said that by the time officers had arrived on the scene "they found a few people have been shot. A couple were dead at that point."
"We also found who we believed to be the shooter and still believe to be the shooter, because he had a long rifle and pistol with him."
The Tulsa shooting follows two other mass shootings in the United States in May.
Last week, a gunman killed 19 children and two teachers at an elementary school in Uvalde, Texas. Yesterday, US President Joe Biden pledged to meet with Congress to discuss gun laws in the wake of the shooting.
Earlier in May, a shooter killed 10 people at a supermarket in Buffalo, New York.