A woman has died and three other people are in hospital after a shooting at a synagogue outside San Diego.
San Diego County Sheriff William Gore said that a white man entered Chabad of Poway on Saturday and opened fire on worshippers with an AR-type assault weapon.
Mr Gore said an off-duty Border Patrol agent believed to be inside the synagogue shot at the suspect as he fled.
The sheriff said the agent did not hit him but struck his car.
The shooting happened on the last day of Passover at about 11.30am, local time (7.30pm UK) at the synagogue in Poway, about 25 miles northeast of San Diego.
San Diego Police Chief David Nisleit said a 19-year-old suspect called police to report the shooting and a California Highway Patrol officer heard it on a police scanner, saw the suspect and pulled him over.
Mr Nisleit said the suspect got out of his car with his hands up and he was taken into custody without incident.
Mr Gore said a woman died from her injuries, while a girl and two men are in the hospital.
The Official San Diego County Sheriff's Department Twitter account earlier said: "Be aware of increased law enforcement activity in the 16000 block of Chabad Way as @SDSOPoway Deputies investigate reports of a man with a gun.
"Please stay clear of the area and allow deputies to safely do their job. Thank you for your patience and cooperation."
It later give a brief update on those injured but did not confirm how many casualties there were or the nature of their injuries.
The San Diego sheriff added: "Please don’t spread misinformation that could cause concern or panic.
"We urge you to allow deputies to safely do their job.
"This is a developing situation and the information provided here may later change."
The shooting comes six months after eight men and three women were gunned down in the Tree of Life Synagogue in Pittsburgh.