Police have detained 11 people for their involvement in Friday's shooting in Shanghai that left two persons dead.

An argument between two gangs over repayment of a debt turned violent, leading to the shooting in Putuo district around 12:30 pm on Friday, police said.

A man shot in the head died in Huadong Hospital on Saturday. Another gangster, who witnesses had said was injured in the clash, died late on Friday night, police said.