Police in the Bay Area were investigating swatting incidents at multiple schools in San Jose, Oakland, San Francisco, and more towns on Wednesday.
The fake reports of shooters were intended to draw a large police response, which is known as swatting.
In San Jose, police said they received a "hoax" call from someone claiming there were multiple students shot at Lincoln High School on Wednesday.
"The call was a hoax and unfounded," police said. "We will investigate the caller."
A prank call about a threat to Oakland's McClymonds High School prompted police to investigate, authorities told KTVU. It was a bogus call as well.
Oakland Unified spokesperson John Sasaki said, "anytime you have police coming in ready to deal with a mass shooter, it’s something that has them very heightened. It raises alarm levels anywhere."
George Washington High School in San Francisco was also the subject of a phony report.
Police in South San Francisco say a swatting incident occurred at South San Francisco High School and as a result, the school was placed on lockdown. There was "no merit" to a report of an active shooter on campus, police said.
Police say they checked the campus and lifted the lockdown.
A similar incident happened at Woodside High School in San Mateo County. An alert sent out by the county said the school was also in a lockdown while law enforcement checked the campus.
An unidentified school in Fremont was placed on lockdown while police officers and firefighters responded to an untrue report of a shooting, the police department there said.
In Belmont, police said they would add more officers to school campuses there as a precaution because of the bogus calls in other areas.