US authorities have appealed for help in finding the person responsible for a shooting that left four people dead, three of them children, at a birthday party at a banquet hall in California.

Heather Brent, a spokesperson for the San Joaquin County sheriff’s office, said the children killed in Saturday’s shooting were aged eight, nine and 14. She said a 21-year-old also was killed in the attack during the party in the city of Stockton.

“This was a birthday party for a young child, and the fact that this happened is absolutely heartbreaking,” Ms Brent said at a news briefing on Sunday at the site.

The sheriff’s spokesperson said the search continues for possible suspects. No arrests have been made.

Faith leaders in the Stockton area were planning a Sunday afternoon vigil to honour the d

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