Police officers are negotiating Saturday evening in Fremont with a man who has barricaded himself in a vehicle near Mowry Avenue, between Peralta and Mission boulevards.
Union City police are assisting Fremont officers, as the incident with the man began in Union City.
The vehicle is parked in the area of Crosspointe Common and Muirfield Terrace, near Cherry Lane.
Residents in the immediate area are being asked to stay indoors as a precautionary measure until further notice.
There are no further details at this time.