display
Four people, including a child, were killed in another armed incident in California.
In addition, a woman was critically injured when a shooter opened fire in an office building in the southern California city of Orange on Wednesday (local time), the police said, according to local media.
Police spokeswoman Jennifer Amat said the alleged perpetrator was injured after an exchange of fire with the officers.
His condition is critical.
The background to the fact is still completely unclear.
Hours earlier, two people were killed and three others injured in gunfire in the US capital, Washington.
It was apparently about the escalation of a dispute between two groups, said police chief Robert Contee.
The injured were not in mortal danger.
"Orange is usually quiet"
display
At the crime scene in Orange, a two-story building with several offices and smaller shops, a firearm was seized, it was said.
The complex houses a family therapist, an insurance company and a real estate agent, among other things.
The police were called around 5:30 p.m. (local time) after gunfire was heard there.
The city, which has around 140,000 residents southeast of Los Angeles, has not experienced such an act since 1997, the police spokeswoman said: "Orange is usually quiet." At that time, a shooter who had previously lost his job killed four people before he left the police was shot.
"It's awful and heartbreaking," tweeted California Governor Gavin Newsom.
In the United States, it was the third comparable incident with at least four deaths in around two weeks.
On March 22, a gunman killed ten people in a supermarket in the state of Colorado.
A few days earlier, eight people had been shot dead in three massage parlors in and around Atlanta, Georgia.
In the United States, there are regular fatal incidents involving firearms that are easy to buy there.
The recent attacks reignited the political discussion about tougher gun laws in the country.