Monterey County deputies sheriff's said someone reported the gunman at a home on Bardue Street about 12:30 p.m.
It was not clear if someone was threatened or what triggered the call, said Sgt. Mike Burns. A SWAT team responded and remained there late Thursday afternoon.
"There is a person in the house with a gun. It's still ongoing and we don't know all the details," Burns said.
The elementary and middle school at 365 Vega St. is about two blocks from Bardue Street. Students were being released to their parents.