Multiple people have been killed and wounded after gunfire erupted at a railyard in California, and a sheriff's spokesman said the suspect is dead.
Santa Clara County sheriff's spokesman Russell Davis said he could not specify the number of dead and wounded or describe how the suspect died during the incident in San Jose.
The shooting took place around 6.30am at a light rail facility next door to the sheriff's department and across a motorway from the airport.
The facility is a transit control centre that stores trains and has a maintenance yard.
Mr Davis said he did not know the type of weapon used or whether the shooting happened indoors or outdoors. He said the victims include Valley Transportation Authority employees.
The VTA provides bus, light rail and other transit services throughout Santa Clara County, the largest in the Bay Area and home to Silicon Valley.
Oakland television station KTVU aired an interview with an unidentified man who said his mother hid from the assailant in a room with her co-workers.
"Our hearts are pained for the families of those we have lost in this horrific shooting," San Jose mayor Sam Liccardo said on Twitter.
California governor Gavin Newsom said in a tweet that his office was "in close contact with local law enforcement and monitoring this situation closely".
Special agents from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives were responding to the crime scene, officials said.