The five-year-old girl and 35-year-old shopkeeper who were shot during a fight between gang members in a shop in Stockwell on Tuesday night both remain in a critical condition.
The five-year-old girl, believed to be the youngest gun victim in Britain, was shot in her chest, with the bullet narrowly missing her heart.
The shop keeper was shot in the face.
Both victims are said to be in a critical but stable condition.
The police is looking for three youths who are believed to have chased two others into the shop at about 9.15pm on Tuesday night, before they opened fire.
Det Ch Insp Tony Boughton said: “This is a terrible incident where an innocent child has been seriously injured.
“We want to hear from the local community, who might have seen these youths cycling around the estate between 9pm and 10pm.
The police would also like to speak to the pair who were chased into the shop.
“They are an important part in helping us understand exactly what was happening and should be able to direct us to those responsible,” Boughton said.
The inspector also appealed to anyone who had any information or were involved in the shooting to come forward and assist the police in the investigation.
“These criminals have seriously injured two innocent bystanders and must face the consequences of their actions,” he said.