Police were called to the incident at the Chabad of Poway synagogue near San Diego shortly before 11.30am local time.
San Diego County Sheriff’s Department tweeted: “There are injuries. This is a developing situation.”
In an earlier tweet, Sheriff Bill Gore said: “Please stay clear of the area and allow deputies to safely do their job.”
At least four victims were taken to hospital, according to local channel KGTV 10News.
A man has been arrested in connection with the incident.
It is the last day of Passover and the synagogue had advertised on Facebook a service starting at 11am.
The shooting comes six months after a gunman killed 11 people and wounded six others after storming a Pittsburgh synagogue.
This is a breaking story. More to follow.
source: express.co.uk