Six hurt during shooting at San Francisco party.

Six people,  five of them teens, were injured when gunfire erupted at a girl's 16th birthday party in the San Francisco Bay area,  said  authorities on Sunday.

Police believe three or four male partygoers opened fire Saturday night when two groups  started arguing. Per police, "Violence is not common in the neighborhood in Antioch, which is about 38 miles northeast of San Francisco."

"Weapons were shown and multiple shots were fired from various guns," Willerford said.

Among the wounded a 13-year-old boy, two 16-year-old boys, two 18-year-old men and a 21-year-old woman, police said. Their injuries ranged from a minor grazing wound to an abdomen wound, police said. Some have been released from hospitals.