At least four people were killed, including the gunman, when a disgruntled United Parcel Service employee opened fire at a company package sorting hub in San Francisco, two local TV news stations reported.
After firing on co-workers, the suspect turned a gun on himself when confronted by police, according to NBC Bay Area and ABC 7.
He later died at an area hospital, they said, citing law enforcement sources.
Victims were taken to the Priscilla Chan and Mark Zuckerberg San Francisco General Hospital, spokesman Brent Andrew said.
He said he could not say how many patients were taken to the hospital or give their conditions.