Several people were killed and others were wounded when a person with a gun opened fire in a light rail yard in San Jose, California, on Wednesday, the county sheriff's office said.
Santa Clara County Sheriff's Deputy Russell Davis told reporters that there were "there are multiple injuries and multiple fatalities" and the shooter was now dead.
"I can't confirm the exact number of injuries and fatalities," he said. He said he could not identify the shooter or confirm how they died.
The shooting took place a little before 7 am PT (1400 GMT) at a light rail yard run by the Santa Clara Valley Transportation Authority near the city's main airport.
"The shooter is no longer a threat, and the facility has been evacuated," San Jose Mayor Sam Liccardo wrote.
San Jose, a city with about 1 million residents, lies at the heart of Silicon Valley, a global center of technological innovation and home of some of America's biggest tech companies.
Davis said he would share more information later.
A local ABC News affiliate reported that the building was not open to the public, so the shooter would have needed employee access or to have broken in. News footage of the yard showed a cluster of industrial hangar-like buildings adjacent to rail tracks.