A female ex-postal worker has shot dead six people at a sorting office in California, before committing suicide.
Santa Barbara police teams sealed off the building
One other person is in a critical condition, the authorities said.
The incident took place at around 2115 local time on Monday (0515 GMT on Tuesday) in the coastal town of Goleta, near Santa Barbara.
More than 50 people were working at the 24-hour sorting office at the time of the shooting. All the victims were believed to be postal workers.
Police responding to reports of shots found two people dead outside the sorting office.
Inside the building, they found another two injured women, one of whom later died in hospital. The other is in a critical condition with a gunshot wound to the head.
Three more victims and the body of the attacker were found in a subsequent search of the building.
The name of the attacker has not been disclosed, but she is said to have worked at the plant in the past.
US Postmaster General John E. Potter in a statement spoke of "complete shock" at the shooting and said that counselling would be offered to families and employees.
"Our heartfelt prayers and condolences go out to the families of the victims and to our employees who have suffered through this tragic incident," he said.