The incident took place on Sunday when the Dalit girl's parents had gone to work and her uncle identified as Sukhbir lured her to come along and locked her in a room, they said.
Sukhbir along with four of his friends then gangraped the minor.
Yesterday, the girl poured kerosene and tried to set herself ablaze following which she received 70 per cent burn injuries, they said, adding, she was rushed to Delhi's Safdarjung Hospital in a serious condition.
Upon receiving information about the incident, Senior Superintendent of Police Manjil Saini and DIG Laxmi Singh met with the family and assured that the National Security Act will also be invoked in the case.