Police officer shot dead in San Diego

One police officer has died and another has undergone surgery after they were shot while making a traffic stop in San Diego.

San Diego Police Chief Shelley Zimmerman said the anti-gang crime officers reported they were making the stop shortly before 11pm on Thursday and almost immediately radioed for emergency cover.

Responding officers immediately put one of the wounded men into a patrol car and sent him to hospital but efforts to save him failed. Ms Zimmerman said that the officer had a wife and two children.

She said doctors are hopeful the wounded officer will survive. His wife is with him at the hospital.

Video footage from the scene showed officers out in force with numerous squad cars, emergency lights flashing, officers on foot and a helicopter buzzing overhead.

The police department said in a tweet that one suspect is in custody and other possible suspects are being sought.

The shooting comes as police across the US remain on high alert following the killing of officers in Dallas and Baton Rouge, Louisiana, earlier this month.