Search for missing girl, 6, captures the nation in South Africa

The South African navy has been brought in to help with a search for Joslin Smith

Hundreds of community members have also been involved in the search for Joslin Smith (AP)

The case of a missing girl has captured the nation in South Africa as the navy was brought to help with the search.

Joslin Smith, 6, has been missing for three weeks after disappearing on February 19 in the Saldanha Bay area on South Africa's west coast, about 120 kilometers (75 miles) north of Cape Town.

Police, firefighters and specialized dog units have scoured sand dunes and scrub land near the informal settlement of shacks and small houses where Joslin lived.

Search teams have used drones to view large areas of ground, police said, and personnel from a South African navy base in Saldanha Bay have now bolstered the operation.

Hundreds of community members have also been involved in the search, and some of them claimed this weekend to have found a knife and a girl's clothing stained with blood, which they said they handed over to police.

Police said they had sent items found during the search to a laboratory for forensic examination without saying what exactly was discovered.

This photo supplied by the South African Police Services shows a photo of Joshlin Smith who went missing on February 19 (AP)

Police Minister Bheki Cele met with Joslin's family on Saturday and pleaded for calm among local residents after anger erupted over the young girl's disappearance. Joslin's mother, Kelly Smith, said she and her boyfriend had to be kept at a police station for their own protection last week after angry neighbors blamed them.

Police did not comment on that but Cele asked for the community to remain calm “amid the finger-pointing.”

Kelly Smith said she asked her boyfriend to look after Joslin when the young girl felt unwell and didn't go to school on the day she disappeared. The boyfriend, Jacquin Appollis, said he lost track of where Joslin was.

The Missing Children South Africa charity, which is helping in the search for Joslin, says police statistics indicate a child goes missing every five hours in the country. Around a quarter of the missing children are killed, trafficked or never found, it said.

Police also launched a separate search for a 3-year-old boy who went missing in another town near Cape Town on Sunday.