A seven-year-old South African girl has shot dead her friend, aged six, with her grandfather's revolver while playing at a farm, police say.

A murder case has been opened after the dead girl, a daughter of a farm worker, was shot in the face, reports say.

The alleged killer's grandfather has been charged with failure to safeguard a firearm, police added.

South Africa has tight gun ownership regulations but many people still possess firearms.

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